User:JDinauer/sandbox

Week 2

Article Evaluation: Hagfish https://en.wikipedia.org/wiki/Hagfish

• Is everything in the article relevant to the article topic? Is there anything that distracted you?

Everything in the article is relevant.

• Is the article neutral? Are there any claims, or frames, that appear heavily biased toward a particular position?

The article is neutral and does not make any claims heavily biased towards any position.

• Are there viewpoints that are overrepresented, or underrepresented?

There are no overrepresented or underrepresented viewpoints.

• Are citation properly formatted?

Citations are properly formatted.

• Do the links work?

The link citing the commercial uses of hagfish skin leads to a dead website.

• Does the source support the claims in the article?

The linked sources support the claims that they are citing.

• Is each fact referenced with an appropriate, reliable reference? Where does the information come from? Are these neutral

sources? If biased, is that bias noted?

The sources are either from research paper or news articles. Most news sources are inherently biased politically, but most articles cited here appear to have a neutral stance and get information from scientific sources or interviews with Hagfish researchers. However, citation 16 (https://nypost.com/2017/10/25/slime-from-this-300-million-year-old-creature-could-create-bulletproof-body-armor/) and citation 44 (https://web.archive.org/web/20091116002431/http://green.ca.msn.com/greenliving/gallery.aspx?cp-documentid=22580760&page=6) are notably unreliable sources. There are also many claims made in the Physical Characteristics and Reproduction sections which lack citation. Additionally, the information that Hagfish is commonly eaten in Korea is taken from someones experiences on the talk page and is not cited. The claim that proximal tube of the nephron is also connected with the coelom, which provides lubrication.

• Are there any instances of plagiarism on the page?

It is likely that some of the information in the Physical Characteristics and Reproduction sections are plagiarized due to the lack of citations.

• Is any information out of date? Is anything missing that could be added?

The information appears up to date, and I couldn't find any missing information. I think that the wording on the classification of the Hagfish could be changed to better reflect that it is firmly within the Vertebrates.

• What kinds of conversations, if any, are going on behind the scenes about how to represent this topic?

There hasn't been any significant conversations in the talk page for years. Most of the past conflict was about Hagfish classification, but recent evidence has put that conversation to rest.

• How is the article rated? Is it a part of any WikiProjects?

It is C-Class. It's apart of the Fishes (high importance), Food and Drink (low importance), and Fisheries and Fishing (mid importance) WikiProjects.

• How does the way Wikipedia discusses this topic differ from the way we've talked about it in class?

The focus is more on providing general information about all aspects of the Hagfish as opposed to being focused on the phylogeny. There are also references to non-scientific facts as well, such as its use in clothing and food.

Lab Assignment Individual Thoughts

A content gap is an area where there is a lack of information or depth. Also, confusing or poorly written information can be a content gap. They can arise from actions such as poor writing, bad/not enough sources, or just a general lack of information on the topic. Wikipedia writers matter because you don't want someone who has no idea how to write, or is very biased to be editing information. Anyone can write if they are able to learn how to be effective. Biased information can come from sources that present biased information, or presenting unbiased information with ones own conclusions. My question is: As there are many news articles cited in this page, should we make an effort to replace them with something more reliable?

Lab Assignment Group Discussion

Kalina's thoughts: A content gap is when there seems to be important information missing. You could identify a content gap if a part of the article seems confusing. This could happen because the writer did not do enough research with reliable resources. This can be fixed by looking at more reliable resources. I think that it does not matter who writes Wikipedia as long as he or she does proper research and has a good understanding of the topic. To be unbiased on Wikipedia means to keep your personal opinions out and focus on the facts. This is similar to how I think of being unbiased. Regarding my assigned article, I had a question regarding the phylogenetic tree. I was wondering what the cross next to Myxinikela siroka indicates. I felt like more could have been said about the phylogenetic tree.

Group Evaluation : The phylogenetic tree is a bit confusing and could use more information. The symbol next to Myxinikela siroka, for example, is not explained in the description. It could be an improvement if a less focused tree was used to better show the Hagfish's place in the Chordata phylum and in the evolution of vertebrates.

Week 3

Individual Assignment

Method: Add a new citation that supports existing content that is either uncited, has an existing citation that is low quality or needs a citation altogether.

I did not make this edit to the actual article.

Section: Feeding

Statement: While polychaete marine worms on or near the sea floor are a major food source, hagfish can feed upon and often even enter and eviscerate the bodies of dead and dying/injured sea creatures much larger than themselves. They are known to devour their prey from the inside.^[44]

Current Citation: Wilson, Hugh (November 2009) Hagfish – World's weirdest animals. green.ca.msn.com

Proposed Citation: Edwards, Susan L.; Goss, Gregory G. (2015-09-14). Hagfish Biology. CRC Press. ISBN 978-1-4822-3346-9.

Comment: "While polychaete marine worms on or near the sea floor are a major food source" should be changed to "While polychaetes and shrimps on or near the sea floor are a major food source" if the proposed citation is used.

Section: Slime

Statement: Hagfish thread keratin (EsTKα and EsTKγ; Q90501 and Q90502), the protein that make up its slime filaments, is under investigation as an alternative to spider silk for use in applications such as body armor.^[16]

Current Citation: "Slime from this 300 million-year-old creature could create bulletproof body armor". New York Post. 2017-10-25. Retrieved 2017-10-26.

Proposed Citation: Sushila; Singh, Saroj S. Jeet; Devi, Sarita (2020). "Hagfish slime: The future clothing". Journal of Entomology and Zoology Studies. 8 (4): 372–375. ISSN 2320-7078.

Comment: "(EsTKα and EsTKγ; Q90501 and Q90502)" should be removed, or moved to its own statement and citation if the proposed citation is used.

Discussion

• Blog posts and press releases are considered poor sources of reliable information. Why?

Blog posts are usually written by a single person for the purposes of sharing opinion, not facts or useful information. Press released are designed to favor the company and tell people what the company wants them to hear.

• What are some reasons you might not want to use a company's website as the main source of information about that company?

Similar to press releases, company websites are inherently biased towards themselves and tend to place themselves in the best light possible.

• What is the difference between a copyright violation and plagiarism?

A copyright violation is when you use someones information that is not able to be freely used, even if they are cited. Plagiarism is using information available to the public without citing its owner.

• What are some good techniques to avoid close paraphrasing and plagiarism?

The best way to avoid plagiarism is to state information in your own words. Avoid just changing the sentence structure of the cited material or using excessive quotations. Looking at multiple sources can help with framing your information to not be plagiarism or close paraphrasing.

Feedback: Discussion and Adding to an Article

• I like the discussion items here. One of our biggest challenges will be finding good images to use/contribute and here is where copyright concerns will enter
• I am really appreciating the way you decided to organize your comments. It is very easy to navigate and understand.
• One thing I would encourage you to try here in your sandbox, is the use of the citation tool. In many ways, it is quite easy to use and very handy....but sometimes it can be touchy. Practice really helps
• I think your suggestions are REALLY good and definitely beneficial to the quality of the article. I'd like to see you submit at least one to the article talk page (this is ABSOLUTELY up to you).
• A benefit of doing that is the potential feedback of other Wikipedians working on this page. They can help direct your potential edits and point you in useful directions.
• Finally, get in the habit of "signing" your additions....I am modeling at the end of this set of feedback. Just use the characters or click on the "sign your posts on talk pages" icon below. Osquaesitor (talk) 16:56, 9 March 2021 (UTC)

Week 4

Choice 1: Shark

I chose the shark because of their fascinating cartilaginous skeleton and their constantly replacing teeth. Improvements that could be made to this page include adding information on their cartilaginous skeleton and the addition of a section on shark internal anatomy.

Associated links: Shark anatomy, cartilaginous fish, Fish scales (Placoid scales).

Choice 2: Hagfish

I chose the Hagfish because I find the debate regarding their classification and relationship to lampreys and vertebrates to be intriguing. This page could use some work regarding the phylogeny section and the relationship between the Hagfish and the rest of the chordates, and the addition of a description of Hagfish internal anatomy.

Associated links: lamprey, cyclostomes, craniates.

Choice 3: Tunicate

I chose the Tunicates because I think its very interesting how many of them go to a chordate larval form to an adult form that lacks some of the 5 synapomorphies. Some edits that could be made to this page are the addition of articles on specific species of tunicates that are linked, but have no associated wikipedia page, or the addition of information on their metamorphosis.

Associated links: Larvacea, chordates, craniates.

JDinauer (talk) 22:55, 12 March 2021 (UTC)

Week 5

Individual Work

Group Sandbox

Area of Focus: Reproduction

Tentative Information:

: Hagfish posses neuroendocrine-pituitary hormones (like GnRH) secreted from pituitary glands that share structure and function with those found in more recent vertebrates. This provides an image of how reproduction evolved for vertebrates.

: Hagfish may reproduce seasonally, stimulated by GnRH. E. bugeri has an annual reproductive cycle with an annual migration.

: Little is understood about hagfish reproduction due to their deep-sea habitat and the challenge this places on collecting embryos and observing behavior. Hagfish eggs are among the largest of those lain by sea-dwelling vertebrates. They posses velcro like hooks on both ends. The number of egg lain depends on the species. Hagfish testis have been observed to be incredibly small, and their sperm count limited. The amount of mature males recorded in some deep-sea hagfish populations are also very limited. There are three hypotheses based on the observation of the low percentage of males and small tests for deep-sea hagfish fertilization, but there is no direct evidence to support any one of theme. 1) Female hagfish lay eggs in small crevices in rock formations. 2) The eggs are laid in burrow beneath the sand. 3) The slime produced by the hagfish is used to hold the eggs in a small area. Dead-sea surveying equipment has been unable to detect eggs on the ocean floor.

: Some species of hagfish have been shown to be sexually undifferentiated before maturity, and posses gonadal tissue for both ovaries and testis.

Comment: Some of this information is already in the reproduction section, but is not cited.

Images:

https://commons.wikimedia.org/wiki/File:Black_hagfish,_Eptatretus_deani_gonads_01.jpg

(not reproduction but its better than the current feeding picture) https://search.creativecommons.org/photos/62bd389b-999f-4d09-af4d-df6c53f6d5db

Week 6

Original:

Very little is known about hagfish reproduction. Embryos are difficult to obtain for study, although laboratory breeding of the Far Eastern inshore hagfish, Eptatretus burgeri, has succeeded. In some species, sex ratio has been reported to be as high as 100:1 in favor of females. Some hagfish species are thought to be hermaphroditic, having both an ovary and a testicle (only one gamete production organ is in both females and males). In some cases, the ovary is thought to remain nonfunctional until the individual has reached a particular age or encounters a particular environmental stress. These two factors in combination suggest the survival rate of hagfish is quite high.

Depending on species, females lay from one to 30 tough, yolky eggs. These tend to aggregate due to having Velcro-like tufts at either end. Hagfish are sometimes seen curled around small clutches of eggs. If this constitutes actual breeding behavior is uncertain.

Hagfish do not have a larval stage, in contrast to lampreys, which have a long one.

Hagfish have a mesonephric kidney and are often neotenic of their pronephric kidney. The kidney(s) are drained via mesonephric/archinephric duct. Unlike many other vertebrates, this duct is separate from the reproductive tract. Unlike all other vertebrates, the proximal tubule of the nephron is also connected with the coelom, provided lubrication.

The single testicle or ovary has no transportation duct. Instead, the gametes are released into the coelom until they find their way to the posterior end of the caudal region, whereby they find an opening in the digestive system.

The hagfish embryo can develop for as long as 11 months before hatching. This is retarded in comparison to other jawless vertebrates. Information on their embryology has been obscured until recently, when husbandry advances enabled considerable insight into the group's evolutionary development. New insights into the evolution of neural crest cells, support the consensus that all vertebrates share these cells, which might be regulated by a common subset of genes.

The inshore hagfish is the only member of the hagfish family with a seasonal reproductive cycle.

Draft:

Very little is known about hagfish reproduction. Obtaining embryos and observing reproductive behavior are difficult due to the deep-sea habitat of many hagfish species. In the wild females outnumber males, with the exact sex ratio differing depending on the species. E. burgeri, for example, has a nearly 1:1 ratio, while in M. glutinosa females are significantly more common than males. Some species of hagfish are sexually undifferentiated before maturation, and posses gonadal tissue for both ovaries and testis. It has been suggested that females develop earlier than males, and that this may be the reason for unequal sex ratios. Curiously, hagfish tesis are abnormally small.

Depending on species, females lay from one to 30 tough, yolky eggs. These tend to aggregate due to having Velcro-like tufts at either end. It is unclear how hagfish go about laying eggs, although researchers have proposed three hypotheses based on observations of the low percentage of males and small testis. They are 1) Female hagfish lay eggs in small crevices in rock formations. 2) The eggs are laid in burrow beneath the sand. 3) The slime produced by the hagfish is used to hold the eggs in a small area. It is worth noting that no direct evidence has been found to support any of these hypotheses. Hagfish do not have a larval stage, in contrast to lampreys, and are born miniature versions of their parents.

Hagfish have a mesonephric kidney and are often neotenic of their pronephric kidney. The kidney(s) are drained via mesonephric/archinephric duct. Unlike many other vertebrates, this duct is separate from the reproductive tract. Unlike all other vertebrates, the proximal tubule of the nephron is also connected with the coelom, provided lubrication. The single testicle or ovary has no transportation duct. Instead, the gametes are released into the coelom until they find their way to the posterior end of the caudal region, whereby they find an opening in the digestive system.

The hagfish embryo can develop for as long as 11 months before hatching. This differs in comparison to other jawless vertebrates. Information on their embryology has been obscured until recently, when husbandry advances enabled considerable insight into the group's evolutionary development. New insights into the evolution of neural crest cells, support the consensus that all vertebrates share these cells, which might be regulated by a common subset of genes. Hagfish possess Gonadotropins which they secrete from pituitary glands to the gonads to stimulate development. This suggests that hagfish have an early version of the Hypothalamic–pituitary–gonadal axis, which was once thought to be exclusive to the Gnathostomes.

Some species of Hagfish reproduce seasonally, stimulated by hormones from their pituitary gland. E. burgeri is known to reproduce and migrate annually.

Week 8

Lampreyologist Feedback

Group: User:Kanessa192/New sandbox

Anessa

This is an informative addition on lamprey adaptations that I think would fit well as its own section on the lamprey page. Your tone is neutral and you have good citations. I like the hagfish skeleton picture, but I think that getting a picture of a lamprey climbing something or its camouflage would be useful for you additions, if you can find one. I've made some recommendations on some minor sentence changes that I think would improve structure.

• Edits

Different species of lamprey have many shared physical characteristics,. However, the same anatomical structure can serve different functions in the lamprey depending on whether if it is carnivorous. For example, non-carnivorous species use their teeth to scrape algae from rocks for food, rather than drilling into the flesh of hosts. The mouth and suction capabilities of the lamprey not only allow it to cling to a fish as a parasite, but provide it with limited climbing ability so that it can travel upstream and up ramps or rocks to breed. This ability has been studied in an attempt to better understand how lampreys battle the current and move forward despite only being able to hold onto the rock at a single point. Some scientists are also hoping to design ramps that will optimize the lamprey’s climbing ability, as lampreys are valued as food in the Northwest and need to be able to get upstream to reproduce.

Another important lamprey adaptation is its camouflage. Similarly to many other aquatic species, most lampreys have a dark-colored back, which enables them to blend in with the ground below when seen from above by a predator. Their light-colored undersides enable them to blend in with the bright air and water above them if a predator sees them from below. Some species can be distinguished by their unique markings. For example, Geotria australis Gray individuals displays two bluish stripes running the length of its body as an adult. These markings can also sometimes be used to determine what stage of the life cycle the lamprey is in; G. australis Gray individuals lose these stripes when they approach the reproductive phase and begin to travel upstream. Another example is Petromyzon marinus, which shifts to more of an orange color as it reaches the reproductive stage in its life cycle.

Tori

This is a good edit to describe how the synapomorphies exist in lampreys. One thing I noticed was that your reference list is formatted weirdly. I would recommend moving your refnames into your draft to replace the handwritten citations, and then just using references to automatically create the citation list. The sources themselves are appropriate and your tone is neutral. I would also recommend adding your name to your edit heading so that its more clear that this is yours. I don't have any grammar or flow recommendations, but I recommend adding links to the specific parts that you mention.

• Edits

Synapomorphies are certain characteristics that arise in chordate organisms in the process of their development. There are five chordate synapomorphies; notochord, dorsal hollow nerve cord, pharyngeal gills or slit, post-anal tail, and an endostyle/thyroid gland. Similarities between adult lancelets and lamprey larvae include a pharynx with pharyngeal slits, a notochord, a dorsal hollow nerve cord and a series of somites that extend anterior to the otic vesicle. (pg 1050, Diogo, 2015)  The notochord is found medial to the mesoderm during early development. The notochord is an adaption that was made for both swimming and feeding. (pg 1047, Diogo, 2015

Irene

This is useful information regarding the major organs of the lamprey and where they are located. I would recommend adding some pictures of these lamprey parts if possible in so that its easier to follow along with where the organs are. You have good citations and a neutral tone. I would recommend adding your name to the edit heading so that's its easier to tell that this is yours. I've made some suggested changes to sentence structure in order to improve flow, as well as condensed the information into fewer individual lines. I also recommend adding in text links to some of the components you mentioned.

• Edits

The internal anatomy of the lamprey contains various components. Some of these organs include a heart, brain, and intestines, etc. One of the key physical components to the lamprey are the intestines. , which are The intestines are located ventral to the notochord. Intestines aid in osmoregulation by intaking water from its environment and desalinating the water they intake to an iso-osmotic state with respect to blood, and are also responsible for digestion. Intestines aid in osmoregulation by intaking water from its environment and desalinating the water they intake to an iso-osmotic state with respect to blood.

The buccal cavity, anterior to the gonads, are responsible to attaching, through suction, to either a stone or their prey. This then allows the tongue to be able to have contact with the stone to rasp algae or tear at the flesh of their prey to be able to drink their blood. The heart of the lamprey is anterior to the intestines. It contains the sinus, one atrium, and one ventricle protected by the pericardial cartilages. Another organ the lamprey possesses is a brain. Their brain is divided into a forebrain, diencephalon, midbrain, cerebellum, and medulla.

The pineal gland, a photosensitive organ regulating melatonin production by capturing light signals through the photoreceptor cell converting them into intercellular signals, of the lamprey is located in the midline of its body. For lampreys, the pineal eye is accompanied by the parapineal organ. The pineal gland is a photosensitive organ regulating melatonin production. This is done by capturing light signals through the photoreceptors cells converting them into intercellular signals.

Mammalologist Feedback

Group: User:Nautas99/groupsandbox

Brooke

I like the additions that you made to the odd-toed ungulate, as the information you provided seems to be missing from the page. Something I noticed was that your edits don't have in text citations, and it would be good to add those. The source you provided before your proposed additions was good, and your tone is neutral. I think comparing the humerus of ungulates with a picture would fit in well, but I'm not sure what Figure 15.4 is to comment on it. I've made some recommendations for changing sentence structure to improve the flow.

• Edits

Ungulates have stances that require them to stand on the tips of their toes. Equine ungulates with only one digit or hoof have decreased mobility in their limb but this allows for faster running speeds and agility.

Differences in limb structure and physiology between ungulates and other mammals can be seen in the shape of the humerus,. often For example, shorter, thicker bones of the limbs often belong to the largest and heaviest ungulates like the Rhinoceros for example.

Newborn perissodactyls are precocial; meaning offspring are born already quite independent,. Young horses can begin to follow the mother after a few hours.

The section on lifespan of Perissodactyls needs a citation; potentially this source What source?

McKenzie

This is a good addition to the characteristics section discussing the hooves of camelids. I do think that you should add citations for the information you've added here, as that seems to be missing. The source list at the bottom contains reliable sources if those are what you are using, and your tone is neutral. I'm also not sure why you have two separate edits, as I think that you can combine your additions just fine. If you want to add more to your draft, I think rewriting the introduction like you mentioned in your plan would be a good idea. I've suggested some edits that I think would make it flow better.

• Edits

Characteristics: "Camelids do not have hooves; rather, they have two-toed feet with toenails and soft foot pads (Tylopoda is Greek for "padded foot"). Most of the weight of the animal rests on these tough, leathery sole pads. The South American camelids have adapted to steep and rocky terrain, and can adjust the pads on their toes to maintain grip. In these species there is a strong relationship between body mass and surface area, meaning larger members of the species will have larger pad area. The surface area of a camelid's foot pads will can increase with increasing velocity in order to reduce pressure on the feet. Many fossil camelids were unguligrade and probably hooved, in contrast to all living species.

Shelby

This is a very good edit to the economic significance of deer. I especially like how you moved some stuff around so categorize it better. You have good sources for the information that you added. I would recommend adding the citations used in the currently published economic significance page if you are not planning on removing/replacing them in your draft, so that you don't accidentally forget them in your final draft. I've made some potential edits that I think improve structure, including moving the paragraph on automobile damage to be close to the other paragraphs on economy.

• Edits

Deer have long had economic significance to humans. Deer meat, known as venison, is highly nutritious. Due to the inherently wild nature and diet of deer, venison is most often obtained through deer hunting. In the United States, it is produced in small amounts compared to beef but still represents a significant trade. Deer hunting is a popular activity in the U.S. that provides the hunter's family with high quality meat and generates revenue for states and the federal government from the sales of licenses, permits and tags. The 2006 survey by the U.S. Fish and Wildlife Service estimates that license sales generate approximately $700 million annually. This revenue generally goes to support conservation efforts in the states where the licenses are purchased. Overall, the U.S. Fish and Wildlife Service estimates that big game hunting for deer and elk generates approximately $11.8 billion annually in hunting-related travel, equipment and related expenditures. Conservation laws prevent the sale of unlicensed wild game meat, although it may be donated.

Deer have long been bred in captivity as ornaments for parks, but only in the case of reindeer has thorough domestication succeeded. The Sami of Scandinavia and the Kola Peninsula of Russia and other nomadic peoples of northern Asia use reindeer for food, clothing, and transport. Deer bred for hunting are selected based on the size of the antlers. In North America, the reindeer, known there as caribou, is not domesticated or herded, but it is important as a quarry animal to the Caribou Inuit. By 2012, some 25,000 tons of red deer were raised on farms in North America. The major deer-producing countries are the market leader New Zealand, the market leader, with Ireland, Great Britain and Germany. The trade earns over $100 million annually for these countries.

Automobile collisions with deer can impose a significant cost on the economy. In the U.S., about 1.5 million deer-vehicle collisions occur each year, according to the National Highway Traffic Safety Administration. Those accidents cause about 150 human deaths and $1.1 billion in property damage annually. In Scotland, several roads including the A82, the A87 and the A835 have had significant enough problems with deer vehicle collisions (DVCs) that sets of vehicle activated automatic warning signs have been installed along these roads.

The skins make a peculiarly strong, soft leather, known as buckskin. There is nothing special about skins with the fur on since the hair is brittle and soon falls off. The hoofs and horns are used for ornamental purposes, especially the antlers of the roe deer, which are utilized for making umbrella handles, and for similar purposes; elk horn is often employed in making knife handles. In China, a medicine is made from stag horn, and the antlers of certain species are eaten when "in the velvet". Velvet antlers in medicine have been shown to have health benefits including enhancing an enhanced immune system immunity and athletic performance, as well as being an effective treatment for arthritis. Antlers can also be boiled down to release the protein gelatin, which is used as a topical treatment for various skin irritations and is also used in cooking. Among the Inuit, the traditional ulu women's knife was made with an antler, horn, or ivory handle.

Automobile collisions with deer can impose a significant cost on the economy. In the U.S., about 1.5 million deer-vehicle collisions occur each year, according to the National Highway Traffic Safety Administration. Those accidents cause about 150 human deaths and $1.1 billion in property damage annually. In Scotland, several roads including the A82, the A87 and the A835 have had significant enough problems with deer vehicle collisions (DVCs) that sets of vehicle activated automatic warning signs have been installed along these roads.

Since the early 20th century, deer have become commonly thought of as pests in New Zealand due to a lack of predators on the island, causing population numbers to increase and move closer to the cities. They compete with livestock for resources, as well as cause excess erosion and wreak havoc on wild plant species and agriculture alike. They can also have an effect on the conservation efforts of other plant and animal species, as they can critically offset the balance within an environment by drastically depleting diversity within forests.

Week 9

Planned Edits:

• Add a picture of hagfish eggs and/or hagfish reproductive organs. I already have a usable picture of hagfish eggs found, but I will have to look for a picture of the reproductive organs. This was the most common piece of feedback I got.
• I'm also go to go through and edit some grammar and word choice based on the copy edits that I received. In particular, I will change how I list the three hypothesis of hagfish production in order for it to have better formatting.

Week 11

Draft 2:

Very little is known about hagfish reproduction. Obtaining embryos and observing reproductive behavior are difficult due to the deep-sea habitat of many hagfish species. In the wild females outnumber males, with the exact sex-ratio differing depending on the species. E. burgeri, for example, has nearly a 1:1 ratio, while M. glutinosa females are significantly more common than males. Some species of hagfish are sexually undifferentiated before maturation, and posses gonadal tissue for both ovaries and testis. It has been suggested that females develop earlier than males, and that this may be the reason for unequal sex ratios. Hagfish testis are relatively small.

Egg development in a female black hagfish, Eptatretus deani

Depending on the species, females lay from one to 30 tough, yolky eggs. These tend to aggregate due to Velcro-like tufts at either end. It is unclear how hagfish go about laying eggs, although researchers have proposed three hypotheses based on observations of the low percentage of males and small testis. The hypotheses are that female hagfish lay eggs in small crevices in rock formations, the eggs are laid in burrow beneath the sand, and the slime produced by the hagfish is used to hold the eggs in a small area. It is worth noting that no direct evidence has been found to support any of these hypotheses. Hagfish do not have a larval stage, in contrast to lampreys.

Hagfish have a mesonephric kidney and are often neotenic of their pronephric kidney. The kidney(s) are drained via mesonephric/archinephric duct. Unlike many other vertebrates, this duct is separate from the reproductive tract, and the proximal tubule of the nephron is also connected with the coelom, provided lubrication. The single testicle or ovary has no transportation duct. Instead, the gametes are released into the coelom until they find their way to the posterior end of the caudal region, whereby they find an opening in the digestive system.

The hagfish embryo can develop for as long as 11 months before hatching, which is shorter in comparison to other jawless vertebrates. Not much was known about hagfish embryology until recently, when husbandry advances enabled considerable insight into the group's evolutionary development. New insights into the evolution of neural crest cells support the consensus that all vertebrates share these cells, which might be regulated by a common subset of genes. Hagfish possess Gonadotropins which secrete from pituitary glands to the gonads to stimulate development. This suggests that hagfish have an early version of the Hypothalamic–pituitary–gonadal axis, a system which once thought to be exclusive to the Gnathostomes.

Some species of Hagfish reproduce seasonally, stimulated by hormones from their pituitary gland. E. burgeri is known to reproduce and migrate annually.