Colugo, or Flying Lemur (Order dermoptera)

•April 3, 2011 • Leave a Comment
Cynocephalus volans

Cynocephalus volans

Colugos, who constitute their own order, are extraordinary in that they are the most proficient of the soaring mammals. There are two species – Cynocephalus voluns and Galeopterus variegatus. They seem also to be extraordinarily not known about, at least by me, until quite recently. I was surprised, because I thought I’d heard of all the flying and soaring mammals, but I had not heard of these.

Galeopterus variegatus

Galeopterus veriegatus

Cynocephalus volans (‘dog-headed flier’?) is found in the Philippines, and is commonly referred to as the Philippine Flying Lemur.

Galeopterus variegatus (I have no idea what this means) is more commonly referred to as the Sunda Flying Lemur, and can be found in Indonesia, Malaysia, Thailand and Singapore.

Neither is a Lemur, though, and neither flies.  Instead, they are a distinct branch of mammals, most closely related to primates.  And they are the only extant examples of Order dermoptera.

The colugos are excellent fliers in part because their patagium (flying flap) is as large as is anatomically possible – extending from the tips of their little colugo fingers and toes, to the top of their little dog-looking noggins and to the end of their tails.  They are built like kites – and can even use their tail flap a bit like a temporary pouch for their babies.  Babies whose job it is to cling to their mom’s body as mom soars around the jungle.

Colugos are arboreal, nocturnal, and they eat small, succulent leaves – but not too many, as it seems that the soaring isn’t too energy intensive, so they don’t need much to be happy. They do not want you to catch them and glue tiny cameras to their heads in order to have a colugo cam, which some naturalist did. But I could not find the colugo cam footage to include here. Instead, here’s a video narrated masterfully by David Attenborough, who I wish would narrate everything for me, and whom I’m sure the colugo would like.

African Wild Dog (Lycaon pictus)

•March 27, 2011 • 1 Comment
African Wild Dog

African Wild Dog

In my opinion, all of the canids are exceptional – but we can make a good case for the African Wild Dog (Lycaon pictus) to be our first canid species appearing here. Also, due to popular demand (thanks, Megan and Ted!).

As Megan noted, these guys are exceptional at least for their bite strength, which is the strongest among the order Carnivora, at least except for maybe some large marsupial carnivores, to whom we shall have to return in other posts. Note the excellent view of African Wild Dog dentition in this photo:

African Wild Dog and Her Teeth

An African Wild Dog showing off her dentition

African Wild Dogs’ teeth have a property shared with a few other canids (the Dhole and the South American Bush Dog). They have one molar shaped with a single crown – which apparently helps them shear off meat and eat very quickly.

And their forelegs are specially adapted to running. They are the only canid lacking dew claws on their front paws, apparently.  This may contribute to their extreme lankiness – look at the long long legs of this AWD, who’s trotting past a car.

Lanky African Wild Dog

African Wild Dog Exhibiting His Lankiness to Great Effect

Like all canids, African Wild Dogs are social critters – but their social organization seems to be different from the others. In the first place, it is patrilocal (girl dogs leave their home pack to find a new one, not boys). Secondly, they do submission-based rather than fighting-based negotiations of rank.

Thirdly, Wikipedia also reports some curious features about AWD’s hunting habits that are both exceptional and problematic for their image with humans. Unlike other canids, AWDs tend to hunt by chasing the bujeezus out of prey in the open over very long distances. Their success rate is something like 80-90% for their typical prey (which are usually some kind of large ungulates, though may also include ostrich) – and that’s just extraordinarily high. But they tend to kill the animal by disembowelment, which is, um, yucky and ugly (though quick in comparison to strategies used by other more popular predators, reportedly).

And sometimes they hunt more dangerous prey – warthogs, for example. Their success rate is a bit lower, but AWD packs seem to develop and pass down specific hunting strategies for these attacks by some kind of social (cultural?) transmission. Different packs have different strategies, and strategies need to be learned by newcomers to these packs.

Like other canids, though, the hunters will bring back meat (usually in their bellies which they have to then puke up) to the den where the pups and adult puppy-sitters wait to be fed.

Pups are extremely cute – and we note two exceptional properties of the African Wild Dog’s appearance here. First, the ginormous round ears; and second, the patched coloration (the ‘pictus’ in their Latin name means ‘painted’) – the latter is more evident than the former in very young pups, as shown here.

Four-week old African Wild Dog pups

Four four-week old African Wild Dog pups

The African Wild Dog is the only extant representative of the Genus Lycaon, and is an endangered species. There are a number of organizations dedicated to protecting and preserving the AWD, and we hope that they are successful.

Here are some AWD pups playing in a pool at the Pittsburgh Zoo.  They are slightly older than the pups above, and have clearly had time for those ears to come in properly.  We urge you to compare and contrast this with the video of the baby elephants playing in a pool in the previous post, please. And note that whatever species you are, if you put a kid in a swimming pool, you know just what she’s likely to do.

African Elephant (Loxodonta africana)

•March 26, 2011 • Leave a Comment

The African elephant is the largest land animal on Earth.  The largest recorded weight for an elephant is 26,000 pounds, but even an average adult African elephant weighs 4.6 tons. They can stand 12 ft tall at the shoulder, carry tusks that weigh up to 200 lbs and are 10 ft in length, eat about 330 lbs of vegetation per day, and drink about 5 percent of their body weight per day.  Elephants will spend most of their day eating grass, leaves, twigs, and bark, approx. 16 hours per day.  Elephants are social animals.  Herds of elephants are lead by a matriarch and are comprised of males up to the age of 15 and females of all ages.  Males separate from the herd at 12-15 years of age and roam on their own.

African elephant

African Elephant

 

Elephant females mature at around age 11, while males mature at about age 15. Despite reaching maturity at around 15 years of age, males will not mate until their mid 20s when they have moved up the social hierarchy. Elephant gestation can take around 22 months: the longest gestation of any animal.  Baby elephants weigh about 200 lbs and stand about 3 ft tall, and have a long life to look forward to of around 70 years in the wild.  The oldest known elephant lived 82 years.  Elephant babies are blind and use their trunks and their mothers as guides to find their way.

Elephant tusks are incisors, not canine teeth.  The tusks at birth are milk teeth which fall out at around 1 year of age.  Adult tusks start to protrude from the lips at around 2 to 3 years of age and continue growing throughout the elephant’s life.  Elephant teeth are gradually produced and are worn away as the elephant ages; the older teeth are pushed forward by the newer teeth and eventually fall out.  This process occurs until the sixth molar is produced.  In most elephants this is the final molar and will last for 2/5th of the animal’s life.  An elephant will usually die when this molar wears out due to starvation or being weakened due to malnutrition.  Rarely, elephants will produce a seventh molar which will extend their life.

Elephants do not grind their food in the same ways that cows do; cows will grind across their teeth from side to side whereas elephants will grind back to front.

Elephants have the largest brains of any land animal.  Elephants are extremely social,using their unique trunks to touch and caress each other.  Elephants have been known to show interest in the bones of other elephants, take care of sick or injured members of their clan, and seem to grieve for dead and dying elephants.  Elephants communicate by trumpeting and also by a deep rumbling sound. These deep rumblings are thought to be detectable for miles.

Elephants are vulnerable, not yet endangered.  They are threatened by habitat loss and poaching by humans.

Here is an example of the cuteness of baby elephants:

What is the smallest animal in the world?

•March 23, 2011 • Leave a Comment

The Tardigrade!

This is a question that many people have answered (incorrectly) on the web.  An animal is a multicellular organism, therefore the answer cannot be an amoeba.  It is not Megaphragma caribea, or fairyfly. The fairyfly is a parasitic wasp that lives on the island of Guadaloupe and feeds off the eggs of other insects. Specimens have been found between 0.10 mm to 0.17 mm in length, which makes it the smallest insect in the world, but there are other animals that are smaller still.  This wasp is smaller than the smallest vertebrate and the smallest mammal, yet all of these are beaten out by a little creature known as a tardigrade.

Waterbear

Waterbear

Tardigrades are also known as water bears or moss piglets.  They range in size from 0.5 mm to less than 0.1 mm in length.  Newly hatched larvae may be 0.05 mm in size.  Tardigrades can survive extremes of temperature and pressure that would kill almost any other animal, ranging from the vacuum of space near absolute zero, to 151 degrees Celcius and pressures of the deepest sea trench.  They can survive about 1000 times more radiation than other animals, and due to their extreme hardiness are encountered from the tops of the Himalayas to the depths of the oceans and from the Arctic to the jungle.

Tardigrada is actually a phylum that contains about 1000 species.  Tardigrada means slow walker, and videos of these animals look like a microscopic bear walking around.

While some species of tardigrades are parthenogenetic, most have both male and female species.  They are oviparous, and usually the male will fertilize the female eggs externally in the moulted shell of the female.  Tardigrades are eutetic, meaning that all adults in each species have the same number of cells.  Tardigrades may have 40,000 cells, some species have fewer.  The young have the same number of cells as adults; tardigrades increase in size by hypertrophy, a process by which an animal increases the size of its existing cells rather than making more cells.

There is a wonderful wiki article about tardigrades here.

Here is a video with rocking music of a waterbear strutting his stuff:

Rotifers may tie in size for the smallest animals.  Finding your own rocking rotifer video is left as an exercise for the reader.

Polar Bear (Ursus maritimus)

•March 20, 2011 • 2 Comments

This post is dedicated to the memory of (cute) Knut, who was born in the Berlin zoo on 5 December 2006, and who died suddenly on 19 March 2011. Yesterday.

Polar bear (Ursus maritimus)

Polar bear (Ursus maritimus)

Knut is kind of a proxy for all of the beautiful and powerful polar bears in the wild whose exceptional abilities to survive in a harsh environment are being tested more and more each year due to climate change and the break up of the polar ice. This change is hardest on the cubs, as they are less able to swim the extra distance it now takes to get from the areas in which they emerged from their dens to the sea ice where they need to go to hunt. Knut was an exceptionally cute cub – but in this way he was exactly like all the other polar bears cubs, in zoos or in the wild. The video below documents his extraordinary powers of cuteness (thank you, Alex Trueman, for finding it).

In what other ways is the polar bear exceptional?

The latin name, ursus maritimus, suggests one – these bears could be classified as marine mammals. Unlike all other ursidae, ursus maritimus spends a great deal of time in the water. Polar bears are graceful and efficient swimmers.

A swimming polar bear emerges from the ice

A swimming polar bear emerges from the ice

Another extraordinary feature of the Polar bear is size. If we classify the Polar Bear as a terrestrial animal instead of an aquatic one, we’ve identified the largest terrestrial carnivore. Well, one of them – the Polar Bear and the Kodiak Bear are tied for this designation. Adult males can be up to 1500 pounds, and almost 10 feet in length.

Ancestral polar bears, ursus maritimus tyrannus, were even larger – below you can get an idea of the size of contemporary and ancient polar bears.

Ursus maritimus tyrannicus vs. Ursus maritimus vs Homo sapiens sapiens

Ursus maritimus tyrannicus vs. Ursus maritimus vs Homo sapiens sapiens

Polar bears are so extraordinarily well-insulated that they are reported to be nearly invisible in infra-red photography. They easily tolerate the most extreme of cold temperatures, and unlike other ursidae, they do not regularly hibernate.

In the wild, polar bears can live up to 30 years, which makes them pretty darned long-lived animals. And they are pretty darned fierce too – hungry polar bears have been known to hunt and eat humans, though they prefer seals. A satiated polar bear may not, however, be so ferocious – and in fact there’s a nice account of a group of bears who have befriended a group of husky dogs:

They seem to be quite curious and smart – and a recent project by the BBC to capture video of polar bears via ‘spy cams’ has generated some truly phenomenal footage. You should check out the BBC page for this programme, and view the clips.

One last controversial claim that must be addressed – some people claimed that when Knut grew up, he became un-cute. While it is clearly true that adult polar bears are majestic and powerful creatures who inspire both respect and fear – we would argue that they are also, decidedly, still cute. Our evidence?

Polar bears being cute, and adult

Grown up polar bears are cute

Cute Knut as a grown-up

Cute Knut as an adult bear - still cute. We will always love and miss you. RIP

Q.E.D.

Elephant seal (genus mirounga)

•March 19, 2011 • 1 Comment
Snuggling elephant seals

This male elephant seal's proboscis is prominently displayed.

Elephant seals are exceptional animals in many ways.  One of these is their size.  A male elephant seal can weigh up to eight thousand pounds – they are, apparently, the largest member of the order carnivora.  They are called ‘elephant seals’ not for their size, but for the male’s proboscis, which I don’t think looks like an elephant’s trunk, but I guess it’s close enough for some people.

‘Elephant seal’ is actually a genus (mirounga), and refers to two species – the Southern elephant seal (mirounga angustirostris) and the Northern elephant seal (mirounga leonina).  The Northern variety are found on the North American West coast,  and they are smaller than their Southern Cousins, who appear in the Southern Hemisphere.  But they are still exceptionally big creatures.

Female elephant seals are cute

Female elephant seals are cute, though also fierce predators.

And as the world’s biggest carnivore, elephant seals have to go to exceptional means in order to feed themselves.  They can dive up to nearly 5,000 feet, and stay submerged for up to 2 hours – which is impressive, to say the least (and accurately reported by Diane Ohala).  If you are an octopus, skate, squid, eel, small shark or penguin, you should be afraid of the elephant seal who may be chasing you around the depths.

As a result, elephant seals know a lot about the ocean.  The Jet Propulsion Labs are currently working with elephant seals (and other pinnipeds) to produce a 3D model of the oceans.  They are apparently gluing transmitters to the heads of their aquatic research assistants.  I hope they are giving them lots of nice rays, skates and eels in return.

giant male elephant seal getting his transmitter from folks working with JPL

This giant male elephant seal is getting a transmitter glued to his enormous head by JPL researchers

And by ‘gluing transmitters’ I mean ‘gluing transmitters’. Per the below instructional video, a ‘powerful epoxy’ is used, and the result is similar to ‘gluing a paperback book onto the back of a 150lb human’. I don’t know about you, but I would find that to be annoying. The elephant seals must be tolerant critters, or there’d be more permanently injured marine biologists.

Updates – March 2011 – New Elephant Seal Photos!  These excellent photos were taken by Diane Ohala on the California coast.  Thanks to Diane for allowing us to post them!

Beachmaster and some girls

A big male and some lovely girls lounging on the beach

Elephant seals are cute.

Cute elephant seals

Mangrove Killifish (Rivulus marmoratus Poey)

•March 18, 2011 • Leave a Comment

The mangrove killifish has to be one of the most unique animals in the world.  This fish is the only known vertebrate that self fertilizes.  In other words, the fish is a hermaphrodite (contains both male and female reproductive organs) and fertilizes its own eggs before laying tiny embryos in water.

As if this weren’t sufficient to place it on this blog, this fantastic little creature has another trick.  It can climb trees.  Yes, you read that right.  When the pools around mangrove trees that support these fish dry up, the fish packs his/her/its bags and climbs up the trunks of mangrove trees and into channels in logs that were carved by insects.  There, placed end to end, the fish curb their normally aggressive behavior and wait (up to several months!) for the pools to return.

Obviously, there is a problem with this strategy.  Fish use gills to take in oxygen from water… so how do they survive for months in the logs of trees without water to breathe from?  The fish alter their gills to retain water and nutrients, and reverse these changes once they return to the water.

killifish

killifish

This killifish video does not show them climbing trees, but it does show a brave killifish traveling overground from puddle to stream to escape predation. And it includes the phrase ‘his kaleidoscopic advances prove irresistable’ (or something like that), and it appears to be true.