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Fat-Tailed Dwarf Lemur: An Interesting Primate That Hibernates

Linda Crampton is a writer and teacher with an honors degree in biology. She loves to study nature and write about living things.

A fat-tailed dwarf lemur in Kirindy, Madagascar

A fat-tailed dwarf lemur in Kirindy, Madagascar

An Unusual and Interesting Animal

Lemurs are interesting and intriguing animals. They are primates, like humans, apes, and monkeys, though unlike these groups they have a pointed face. They are native to Madagascar. The fat-tailed dwarf lemur has the scientific name Cheirogaleus medius. It’s the only primate known to hibernate.

Mouse lemurs (the smallest primates) can enter a state of torpor, which lasts for up to twenty-four hours. The fat-tailed dwarf lemur hibernates for up to seven months, which is an impressive feat. Researchers suspect that studying hibernation in the species may reveal facts that enable humans to travel long distances in space.

The Primate Order

The order Primates contains some interesting mammals. It’s divided into two suborders: Haplorhini and Strepsirrhini. We belong to the first suborder and lemurs belong to the second one.

Suborder Haplorhini

Apes (gorillas, chimpanzees, bonobos, orangutans, and gibbons) have many genes and features in common with us. This is especially true for the first four animals in the list. Monkeys are less similar to humans but are still interesting animals to observe and study. Tarsiers are even more distinctive compared to us but are classified in the suborder Haplorhini as we are.

Suborder Strepsirrhini

Lemurs and their close relatives (including lorises and bushbabies) are sometimes referred to as “primitive” primates. The term means that they are more similar to our ancestors than other primates. Primitive doesn’t mean uninteresting or unimportant, however. The fat-tailed dwarf lemur belongs to the family Cheirogalidae within the suborder Strepsirrhini. The species is shown in the video below.

Lemur Characteristics

Lemurs have pointed and sometimes fox-like faces. As in other primates, their eyes face forward and provide stereoscopic vision. The animals have opposable thumbs and toes and grip objects with their hands and feet. Their digits have nails. The only exception to this rule is their grooming claw, which is generally on the second toe. The tail of lemurs is not prehensile (that is, it can’t grasp objects by curling around them).

Lemurs are often quadrupedal animals. Some species hop sideways with both hind limbs together while their forelimbs are off the ground. The animals don’t walk, however. Sifakas are large lemurs that are almost always in a bipedal position when they are on the ground. Dwarf lemurs are nearly always quadrupedal.

Vision is still being studied in lemurs. It’s believed that most individuals are dichromatic. This means that they can see only two colours: blue and green (plus blends between these colours). This is why videos in this article show the lemurs while they are illuminated by red light, which shouldn’t disturb them. Interestingly, some female lemurs are trichromatic (able to see blue, green, and red), as we are.

Features of the Fat-Tailed Dwarf Lemur

The fat-tailed dwarf lemur is grey or brown. It’s quite a small animal, as its name suggests. Without considering the tail, its body is around eight to nine inches long. The tail is eight to eleven inches long. The animal’s name is based on the fact it stores fat in its tail. It lives on the fat during hibernation.

The animal has a pointed face, but its features are relatively delicate compared to those of some lemurs. The exception is the nose, which is broad and pink. The lemur also has big eyes and is nocturnal. The eyes glow in the dark due to the light-reflective layer at the back of the eyeballs, which is called the tapetum.

The full name of the tapetum is tapetum lucidum. It’s located behind the retina, which is the light-sensitive structure in the eyes. Light rays that travel through the retina without stimulating the light-sensitive cells are bounced back to the retina by the tapetum. This gives them another chance to stimulate the retinal cells and enhances the animal’s vision. It’s especially helpful in very dim light.

Lemurs are native to Madagascar, an island nation off the east coast of Africa. The coloured areas in the map above show the range of the fat-tailed dwarf lemur in the wild. The data for the map was obtained from the IUCN Red List of Threatened Species, species assessors, and the authors of the spatial data.

Habitat and Diet

The fat-tailed dwarf lemur lives in Madagascan forests. Though Madagascar is often thought of a semi-tropical country with a warm climate throughout the year, this is not true everywhere in the island nation. From November to April, much of Madagascar is hot and wet. May to October is cooler and drier. Some areas, such as highland ones, can get cold in winter. It’s believed that the lemur hibernates in response to the dry conditions in its habitat during winter, which interfere with the animal’s food supply.

The animals live in the trees. During the day, they sleep in a leaf-lined hollow in a tree or in a nest-like structure that they create in dense undergrowth. They curl up in the cavity on their own or with up to five other members of their species.

During the night, the lemurs search for food alone. Despite this fact, they belong to a group and have a group range. They have an omnivorous diet that contains a lot of fruit. They also eat flower nectar, insects, and small vertebrates.

Of the 168 fat-tailed dwarf lemurs born at the DLC from our founding through July 2019, 9.52% were singletons, 38.10% were twins, 34.52% were triplets, and 17.86% were quadruplets.

— Duke Lemur Centre

Reproduction and Lifespan

Fat-tailed dwarf lemurs are sexually mature at around the age of eighteen months. The breeding season depends on day length and occurs in summer in the local environment. Gestation lasts from 58 to 62 days. Lemurs seem to most often produce two or more offspring per pregnancy, at least according to studies of captive animals.

In captivity, the females give birth in the artificial nest boxes that are provided. The youngsters stays hidden for a while. If the mother wants to move them to another box, she carries them in her mouth. By the time they are two months old, they move well on their own and act like miniature adults.

Duke University says that the lemurs have lived for over twenty years in captivity. The New England Primate Conservancy says that they have lived up to eighteen years. This reference also says that the animals live between four and eleven years in the wild.

Hibernation, Torpor, and Interbout Arousals

Hibernation in the fat-tailed dwarf lemur consists of two phases, which repeatedly alternate: torpor and interbout arousals. The term “arousal” is used as a comparison to torpor. It’s a metabolic arousal, but it doesn’t mean that an animal leaves its hibernation den and becomes active. The interbout arousals occur every six to ten days during the hibernation period.

Even though its metabolism is decreased for much of the time, the animal requires sustenance during hibernation. It gets this from the fat in its tail. Shortly before hibernation begins, the tail forms up to 40% of the animal’s body weight.

Torpor

Torpor is a period in which an animal’s heart rate, metabolism, and temperature are greatly decreased. According to Duke University, the heart rate drops from around 180 beats per minute to around eight beats every minute. The New England Primate Conservancy says that the breathing rate falls to one breath every ten to fifteen minutes. In addition, the animal’s temperature drops to close to the environmental one.

Interbout Arousal

During an interbout arousal, the animal’s temperature and heart rate increase and its breathing becomes more regular. Observations in captive animals show that the animals experience REM (rapid eye movement) during an arousal, which is an indication that they are dreaming. The phase resembles regular sleep, except for the fact that REM is prolonged. As some researchers have said, it’s almost as though the lemur’s brain needs to dream as much as possible while it’s capable of doing so. The scientist in the video above says that in captivity the arousal state lasts for a few hours. Then the animals fall into a torpor again.

Duke University Studies

In zoos and animal sanctuaries (and the Duke Lemur Center), animals that would normally hibernate in winter often don’t. If they are warm and have adequate food, the stimulus for hibernation doesn’t appear. In their experiments, the researchers at the lemur center try to create environmental conditions similar to those that the animals would experience in the wild during winter.

Needle electrodes are placed under the scalps of the animals so that the researchers can continually record brain activity during hibernation. The animals also wear collars that measure body temperature. The electrode insertion might make some people feel uncomfortable, as it does for me. The animals are anesthetized before the insertion.

A scientist studying the species says that the research group needed to get special permission to perform the studies and that more invasive techniques are prohibited. From a scientific point of view, the insertion and presence of the electrodes are additional factors indicating that conditions aren’t completely natural for the animals in the studies.

The researchers suggest that studying the lemur’s hibernation might be important beyond satisfying our curiosity. Stimulating the natural process of hibernation in captive animals might be good for their health. In addition, the studies may be useful with respect to modifying human biology during long-distance space travel. The researcher in the video says that we have the genes that become active as the lemurs hibernate, but we lack the “switch” to activate the genes,

33 lemur species are Critically Endangered, with 103 of the 107 surviving species threatened with extinction, mainly due to deforestation and hunting.

— International Union for Conservation of Nature (IUCN) in July, 2020

Population Status of Lemurs

Many species of lemurs are in trouble. The scientist in the first video above says that the fat-tailed dwarf lemur is critically endangered. The video was made a year ago. The IUCN Red List page for the species says that its population is ”Vulnerable“ and decreasing. This conclusion was based on a population assessment done in 2018. The scientist’s statement and the 2020 one from the IUCN mentioned in the quote above are worrying. According to the IUCN, only four out of the 107 known lemur species are safe. That’s a shocking statistic.

As the quote above says, a major problem causing the lemur group’s problems is the loss of forests. Forest is also being destroyed to create areas for agriculture. The IUCN says that clearing land for aquaculture is an additional problem affecting the fat-tailed lemur. Another one is hunting. The animals are sometimes caught for food.

World Lemur Day

World Lemur Day is an annual event held on the last Friday of October. It’s associated with an event called the World Lemur Festival. The first festival was held in 2014 in Antananarivo, the capital city of Madagascar. In 2015, the event was celebrated internationally and became linked with World Lemur Day. Two goals of the event are to celebrate the existence of lemurs and to educate the public about their problems. These sound like worthy goals to me, especially if they raise the public’s awareness of the lemur group’s difficulties. The fat-tailed lemur and its relatives need our help.

References

  • Fat-tailed dwarf lemur information from the New England Primate Conservatory
  • Facts about the animal from the Duke University Lemur Centre
  • Colour vision in lemurs from the ScienceDaily news service
  • Description of the Duke Lemur Center experiment from the phys.org news service
  • The hibernating and sleeping animal from Scientific American
  • Population status of fat-tailed dwarf lemur from the IUCN
  • Almost a third of lemur species are critically endangered from the IUCN
  • Threats to lemurs from the BBC (British Broadcasting Corporation)
  • Information about World Lemur Day from the Lemur Conservation Network

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2021 Linda Crampton

Comments

Linda Crampton (author) from British Columbia, Canada on March 23, 2021:

Hi, Heidi. I hope their habitat is preserved, too. I think that protecting lemurs is important.

Heidi Thorne from Chicago Area on March 23, 2021:

They're so cute! I do hope that their habitat is preserved. Thanks for sharing another friend from the animal kingdom!

Linda Crampton (author) from British Columbia, Canada on March 23, 2021:

Thanks for the comment and the suggestion about World Lemur Day, Flourish. Thank you for sharing the other points that you’ve raised as well. I think your point about not sending people into space when the Earth needs our help is important.

FlourishAnyway from USA on March 23, 2021:

It's so sad that we keep clearing forests. We desperately need to curb human population growth. I loved the detail you provided here on this beautiful animal. Those eyes! I think the little critters know they have electrodes implanted; it's not quite natural but if it helps their species survive that is wonderful. I'm not supportive of sending people into space because we've done a number on this planet. Why ruin another one? When World Lemur Day rolls around again, you should share this on social media.

Linda Crampton (author) from British Columbia, Canada on March 22, 2021:

Hi, Mary. Yes, the connection between us and other primates is certainly worth investigating. The research could be helpful for them and for us.

Linda Crampton (author) from British Columbia, Canada on March 22, 2021:

Hi, Devika. Thanks for commenting. I think the lemur is a very interesting representative of its group.

Linda Crampton (author) from British Columbia, Canada on March 22, 2021:

Thanks for the comment, Glenn. I think the lemur and its behaviour are fascinating to explore.

Linda Crampton (author) from British Columbia, Canada on March 22, 2021:

Thank you, Miebakagh. I appreciate your comment.

Mary Norton from Ontario, Canada on March 22, 2021:

This is very interesting especially because they provide more insights into humans. We often take this connection for granted but it has tremendous impact on our health.

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Linda Crampton (author) from British Columbia, Canada on March 22, 2021:

Hi, Chitrangada. Thank you very much for the comment. It is good that some organizations are helping wildlife in trouble, but as you say, a lot more needs to be done.

Linda Crampton (author) from British Columbia, Canada on March 22, 2021:

Hi, Manatita. Yes, I definitely think the animals could be referred to as cute! It does seem that we interfere with the lives of wild animals on a frequent basis. It would be interesting if the researchers discovered that stimulating hibernation does help the lemurs. I appreciate your comment, as always.

Devika Primić from Dubrovnik, Croatia on March 22, 2021:

AliciaC I like this fury Lemur. It is a smart primate and your facts are indeed interesting and informative. I enjoyed reading about this primate. Your research is accurate.

Linda Crampton (author) from British Columbia, Canada on March 22, 2021:

Thank you for comment, Eman. I appreciate your visit.

Linda Crampton (author) from British Columbia, Canada on March 22, 2021:

Hi, Ann. Thanks for the comment. I wonder whether the implants have an effect on the study, too. The situation isn’t completely natural. I assume that the scientists are doing the best that they can to ensure that conditions are as normal as possible for the animals’ sake and to ensure that their discoveries are accurate.

Glenn Stok from Long Island, NY on March 22, 2021:

Linda, I must say that I learned a lot from you about the Fat-Tailed Dwarf Lemur.

The first thing that got me interested was to know how they see in the dark so well, and you answered that question precisely. It’s interesting to know that light is reflected from the tapetum back to the retina, enhancing their vision — as you explained.

I also found the details of its hibernation method fascinating. I had no idea that so many aspects of its biology were involved with that process.

Thanks for writing such an educational article.

Miebakagh Fiberesima from Port Harcourt, Rivers State, NIGERIA. on March 22, 2021:

Linda, although, I've heard some facts about lemurs, I've not read it this far here. Thanks for providing us with the biology, habit, environment, and life of the lemur.

Chitrangada Sharan from New Delhi, India on March 22, 2021:

An excellent and informative article about the Lemurs. I am aware of these sweet creatures, but you have provided wonderful and detailed information about them.

So many wonderful birds and animals are endangered. The governments are taking effective measures, but a lot more needs to be done. Not only by the authorities but by the general public too.

Thank you for sharing this well written and researched article.

manatita44 from london on March 22, 2021:

Wonderful and fascinating account of lemurs. The way they hibernate is very interesting, as is the mention that they can only be found in Madagascar. The reasoning is normal enough.

Looking at some of your videos do help me to see their cuteness and appreciate them more. Some look like large cats. Alas! Seems we always interfere. Yet I do not blame studies that can help in some way. Excellent article

Eman Abdallah Kamel from Egypt on March 22, 2021:

A very informative article. Thank you, Linda, for sharing these interesting facts about Lemurs.

Ann Carr from SW England on March 22, 2021:

What a wonderful animal. Madagascar certainly has some unique species and I hope that status remains, without outside 'contamination'. I'm not comfortable with the implants either! Surely they would affect the study?

Thanks for this great article. Fascinating!

Ann

Linda Crampton (author) from British Columbia, Canada on March 21, 2021:

Thank you very much, Bill. The animal is cute. I hope it survives for a long time to come.

Bill De Giulio from Massachusetts on March 21, 2021:

Another fascinating article, Linda. The Fat-Tailed Dwarf Lemur is a cute little creature. I hope sufficient steps are being taken to insure their long-term survival. Great job.

Linda Crampton (author) from British Columbia, Canada on March 21, 2021:

Thank you very much for the comment, Peggy. The state of the environment can be very discouraging. I hope things improve soon.

Peggy Woods from Houston, Texas on March 21, 2021:

Hi Linda,

You continually educate us about the most interesting subjects. I learned much about the fat-tailed dwarf lemur that I had not known. They are cute little animals, and I hope that their species does not become extinct. Many things are threatened with deforestation practices. When will we ever learn that we need those forests?

Linda Crampton (author) from British Columbia, Canada on March 21, 2021:

Thank you for the visit, Misbah. I appreciate your comment. Deforestation is worrying and sad.

Blessings to you as well.

Linda Crampton (author) from British Columbia, Canada on March 21, 2021:

Hi, Pamela. It’s sad to hear that an animal is endangered. Thanks for the kind comment.

Misbah Sheikh from The World of Poets on March 21, 2021:

Linda, this is a very informative and interesting Hub about Lemurs.

Yes, deforestation is a global problem. I feel sad and sorry for these little cute creatures.

I found the Torpor period very interesting

The videos are very cute

Thanks for sharing

Blessings

Pamela Oglesby from Sunny Florida on March 21, 2021:

This is a very interesting article, Linda. I always hate to know any animal is endangered. I had no idea that the lemur's vision only lets them see green and blue. This is such an informative article, and I learned a lot. Thank you.

Linda Crampton (author) from British Columbia, Canada on March 21, 2021:

Hi, Fran. Yes, deforestation is a major problem in many areas. The situation is worrying. I appreciate your visit and comment.

fran rooks from Toledo, Ohio on March 21, 2021:

Linda, truly interesting article about lemurs. I didn't know there is a world day for lemurs! I believe deforestation is globally happening and hurting all animals, humans, and plant life. Always informative reading your articles. Thank you.

Linda Crampton (author) from British Columbia, Canada on March 21, 2021:

Thank you very much, Bill. I think they are interesting animals to investigate.

Bill Holland from Olympia, WA on March 21, 2021:

All I know about lemurs is they have adorable faces. Oh, I guess I also knew where they came from. But that was the extent of my knowledge until you posted this fine article, so thank you!

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