Sulawesi Dwarf Elephant

Asian Elephant (living relative to the
Sulawesi Dwarf Elephants)

Did you know that back in the Pleistocene there were several species of Elephant that stood only a few feet tall? These animals were all found on islands around the world, and grew smaller in size due to insular dwarfism. Some were found on Cyrpus, Crete, and other Mediterranean isles, some way over in California's Channel Islands, and some on the many islands of Indonesia.

The Sulawesi Dwarf Elephant is a member of that last group. Fossils of this creature have been found on Java and Indonesia, and they date back to around 2 million years ago. One interesting distinction about the species is that they had functional lower tusks, though there is still much to be learned about them and about the species in general.

What we do know is that these Elephants truly were small! They stood only about 5ft at the shoulders, which is a massive difference from the 9ft height of the living Asian Elephants (the two species belong in the same genus).

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Status : Extnict for 1.5 million years
Location : Madagascar
Size : Height up to 5ft (1.5m)

Classification : Phylum : Chordata -- Class : Mammalia -- Order : Proboscidea
Family : Elephantidae -- Genus : Elephas -- Species : †E. celebensis

Image : PLOS

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Steppe Mammoth

Mammuthus trogontherii

The Steppe Mammoth is an interesting creature because it actually predates the Woolly Mammoth that we known so well. These monstrous Proboscideans lived between 600,000 and 370,000 years ago, roaming about the steppes of Europe and Asia.

Steppe Mammoths were one of the largest members of their entire order, living or extinct. At the shoulder they stood around 13ft, which would make them just slightly taller than an average male African Elephant today. Even larger specimens have been found, with some reaching as high as 15ft, and sporting tusks around 10ft long.

Unlike the Woolly Mammoths, whose preserved carcasses have actually been found, and whose skeletons and tusks turn up regularly, the Steppe Mammoth is a more rare find. Most of the fossils found have been teeth, and only a handful of near-complete skeletons have been unearthed. A very rare skull was actually just located in France back in 2008.

Steppe Mammoths most likely followed the Southern Mammoths in terms of evolutionary history, and may have been directly followed by the Woolly Mammoths once the ice age completely set in.

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Status : Extinct for about 370,000 years
Location : Europe and Asia
Size : Height up to 13ft (4m)

Classification : Phylum : Chordata -- Class : Mammalia -- Order : Proboscidea
Family : Elephantidae -- Genus : Mammuthus -- Species : M. trogontherii

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Platybelodon

Platybelodon sp.

Platybelodon is the name of a genus that contained four different species of Proboscideans (the Order also houses our modern day Elephants). They lived between 15 and 4 million years ago, and while they spread across Europe, Asia, Africa, and North America, they didn't make it too far past the Miocene.

Platybelodon was a Gomphothere-- a member of a family that contained several other early-Elephant-like animals that had modified shovel-like tusks (along with the recognizable trunks).

It has long been assumed that those weird lower jaws were used to scoop up aquatic plants, but new fossils with wear patterns have emerged, and a new hypothesis is that Platybelodon used that lower jaw to strip bark. They also had sharp lower incisors that could shear apart plant matter held by the trunk!

Sadly, the Platybelodon and all of its close, Gomphothere relatives are now extinct, and the Elephant line we have today descends from a different family all together.

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Status : Extinct for 4 Million Years

Location : Europe, Asia, Africa, North America
Size : Length around 10ft (3m), Weight around 2 tons (1,800kg)

Classification : Phylum : Chordata -- Class : Mammalia -- Order : Proboscidea
Family : †Gomphotheriidae -- Genus : †Platybelodon

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Tailless Tenrec

Tenrec ecaudatus

Today's animal is native to Madagascar, and has been introduced to the Mascarene Islands. But happily, unlike some of the other critters we've talked about this week, the Tailless Tenrec is not on the verge of extinction! These interesting little mammals actually have a stable population, no major threats, and a wide range.

So now that we've got conservation status out of the way, what on Earth is a Tenrec?! The answer is... interesting. Tenrecs are members of that weird African Superorder known as Afrotheria. Their hodgepodge of relatives includes Elephants, Manatees, Hyraxes, Aardvarks, and Sengi. Tenrecs themselves look a bit like shrews or opossums, and some species even resemble Hedgehogs. This is due to convergent evolution-- Tenrecs evolved to fill the ecological niches that were normally filled by the aforementioned creatures. They May look alike and act alike, but they aren't actually related!

The Tailless Tenrec is the largest of the land-dwelling Tenrecs. They actually do have tails, despite the name, though the tails are very, very short. They look a bit like a Shrew crossed with a Hedgehog, and the younger Tenrecs even have spines to protect them while they grow up (adults have long, coarse hairs).

The Tailless Tenrec is one of the largest insectivores in the world. They detect prey with their long whiskers (they are nocturnal), and capture it with their mouths. Aside from insects, they do also feed on small vertebrates and plants.

You will only really see these Tenrecs in groups during a  few times each year-- during the breeding season when males attract mates, and after the young are born when females are taking care of their offspring. They are very solitary otherwise. Tailless Tenrecs can have massive litter sizes-- up to 32! The young are helpless for the first week or so, but they grow fast and will be on their own after about 5 weeks. They reach sexual maturity around 6 months of age.

Tailless Tenrecs communicate in a number of different ways. When threatened, the ridge of hair on their back rises up. They also hiss, squeal, and even scream!

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IUCN Status : L:east Concern
Location : Madagascar, Mascarene Islands
Size : Length up to 15in (39cm)

Classification : Phylum : Chordata -- Class : Mammalia -- Order : Afrosoricida
Family : Tenrecidae -- Genus : Tenrec -- Species : T. ecaudatus

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Southern Tree Hyrax

Dendrohyrax arboreus

The Hyrax is such a weird little animal! There are four different species within three genera, all of which are found in Africa and the Middle East. They look like rodents, digest their food like ungulates, but are most closely related to Elephants and Manatees. So bizarre.

As a side note to that-- the Superorder Afrotheria encompasses several genetically distinct animal species that all evolved on the African continent, share a common ancestor way back, and have no other close relatives. Sengis, Aardvarks, Elephants, Manatees, and Golden Moles are also members of this interesting group.

You may already know about the more common Rock Hyrax (they are fairly popular in Zoos)-- a ground dwelling, diurnal member of the family that is found across Sub-Saharan Africa with the exception of dense, forested areas. The Southern Tree Hyrax is just the opposite. They live in trees (if the name didn't give that away), are found in the denser forests that the Rock Hyrax is absent from, and live a nocturnal lifestyle.

The Southern Tree Hyrax lives either alone or in very small groups (another opposite of the large clan dwelling Rock Hyrax), and males can be incredibly territorial, making loud shrieking, screaming noises to keep others away. Because they spend their lives almost exclusively in trees, they are incredibly awkward when moving on the ground. Their dens are even constructed in tree holes, or in the nooks between two branches. Twigs, leaves, fruits, and seeds make up their diet.

The Southern Tree Hyrax is able to avoid a lot of different predators by staying off the ground, but they can't avoid the Verreaux's Eagle! This large Bird of Prey is a Hyrax specialist, and most of their diet is made up of the small mammals.

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IUCN Status : Least Concern
Location : Africa
Size : Length up to 28in (70cm)

Classification : Phylum : Chordata -- Class : Mammalia -- Superorder : Afrotheria
Order : Hyracoidea -- Family : Procaviidae -- Genus : Dendrohyrax -- Species : D. arboreus

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Giant Golden Mole

Chrysospalax trevelyani

Oh Classification, you can be so confusing, and so contentious! Moles. Burrowing, insectivorous animals that have tiny or no eyes and giant claws. You'd think they'd all be closely related, right? Nope. There are actually True Moles, Marsupial Moles, and Golden Moles. They all belong to completely different orders and are examples of what convergent evolution can do!

Today's animal, the Giant Golden Mole is (unsurprisingly) one of the Golden Moles. This group of 21 species is found only in southern Africa, and the Giant itself is endemic to the nation of South Africa. They belong to the same Order as the Tenrecs, which itself is part of that odd hodgepodge Superorder known as Afrotheria. That's right, the Giant Golden Mole is technically more related to Manatees and Elephants than it is to the True Moles. Weird how that all works out!

Giant Golden Moles are not, in fact, golden. Their fur is a dark brown. They have powerful front claws and shovel-like back claws that let them scoop out dirt behind them white digging, and they have no external eyes or ears... though they do have a weird leathery pad that protects their nostrils while they dig. In short, they are very well adapted to living underground. Though interestingly, they don't live exclusively under the earth like others of their type; at night they forage for insects and other invertebrates inside of the surface leaf litter! Giant Golden Moles also have the distinction of being the only Golden Mole with any real semblance of a social structure. While they are mostly solitary, they have been observed hibernating in groups.

Giant Golden Moles are becoming quite rare, and are extinct in many localities. They need to live in very specific habitats, namely forested areas with deep leaf litter, soft soil, and a generous amount of undergrowth. Artificial forests and farmlands will not do for these little guys, and as a result they are losing their habitat and becoming incredibly fragmented. There are currently no specific conservation actions underway for the Giant Golden Mole, though they may occur in a few protected reserve areas.

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IUCN Status : Endangered
Location : South Africa
Size : Body length up to 9in (23cm)

Classification : Phylum : Chordata -- Class : Mammalia -- Order : Afrosoricida
Family : Chrysochloridae -- Genus : Chrysospalax -- Species : C. trevelyani

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West Indian Manatee

Trichechus manatus

As I write this there are four living Sirenian species in the world. Three are Manatees, and one is the Dugong. The order gets its name from the Sirens of Greek myth, and there are legends of sailors mistaking this giant aquatic mammals for mermaids!

The West Indian Manatee is one of the three living Manatees, with the African and the Amazonian being the other two. Though they live exclusively in the water like Whales do, they aren't closely related at all. Their nearest living relatives are actually the other members of the Afrotheria superorder- Elephants, Hyraxes, Sengis, and Aardvarks. The Manatees and Dugongs evolved from wading African herbivores millions of years ago.

West Indian Manatee eating

West Indian Manatees can be found in the Caribbean, as well as along the coast of Central and South America. They can live in both fresh and saltwater, and make their homes in rivers, estuaries, canals, and other coastal, slow-moving waters that give them a steady food supply. Manatees are herbivores that feed on floating, aquatic plants. They can eat up to 150lbs of food every single day!

Did you know that the West Indian Manatee is a migratory species? Though they normally only travel at around 5mph (a very brisk walking speed for a human), they can move hundreds of miles in a year. In the United States they have been seen as far north as Massachusetts and New York over the summer months, though those occurrences are very rare.

West Indian Manatees live long, slow lives when compared to some other mammals. They can live as long as 60 years, they have long gestation periods (up to 14 months), and very lengthy reproductive cycles that can mean several years between calves.

The slow reproductive rate has been one of the things holding back the conservation effort. You see, West Indian Manatees were once hunted for their meat, skins, and oil, and they continue to be threatened by fast moving watercraft and by habitat loss. They are listed as Vulnerable by the IUCN, and are protected by the United States Endangered Species act, but it is a a very slow path to recovery, since they breed so slowly and because the human population in their area only continues to grow.

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IUCN Status : Vulnerable
Location : South America and Caribbean Islands
Size : Length up to 11ft (3.5m), Weight up to 1,200lbs (544kg)

Classification : Phylum : Chordata -- Class : Mammalia -- Order : Sirenia
Family : Trichechidae -- Genus : Trichechus -- Species : T. manatus

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Pygmy Mammoth

When one thinks about Mammoths, they probably conjure up images of absolutely gigantic, hairy elephant-like mammals. The Pygmy Mammoths of the Channel Islands skew that image a bit- many were less than half the size of their mainland relatives!

At some point tens of thousands of years ago, a group of Columbian Mammoths made a six mile swim out to Santarosae, a "superisland" that existed when the ocean was 300 feet lower. Today only the very highest land points remain above water, and form four of California's Channel Islands.

Pygmy Mammoth Model from the Field Museum

Why did these 14ft tall, 20,000lb Mammoths swim so far? Perhaps they were allured by the smell of food! Mammoths, and modern Elephants, are excellent distance swimmers thanks to their trunks and buoyant bodies, so travelling a few miles for a buffet of fresh vegetation is a definite possibility!

Once on the island the Mammoths bred and the population grew. At the same time, the water levels rose, creating a larger gap between the island and mainland and trapping the Mammoths. As the number of animals rose, the amount of food fell. Having a smaller size (and thus requiring less sustenance)  became the favored trait, and the Columbian Mammoths evolved and diverged into a new species.

Pygmy Mammoths were comparable in size to our modern Clydesdale Horses. They rarely stood larger than 7ft and weighed around 2,000lbs. A very far cry from the species they evolved from!

Fossils have been discovered on four of the Channel Islands, with the first specimens uncovered in the 1870s. A near-complete skeleton was unearthed in 1994.

Radiocarbon dating has shown that Mammoths were living on the islands for over 40,000 years. However, the species went extinct around 11,000 years ago, which was around the same time that many of the mainland megafauna species were also dying out.

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Status : Extinct for 11,000 years
Location : Channel Islands, California
Size : Height up to 7ft (2.1m), Weight up to 2,000lbs (910kg)

Classification : Phylum : Chordata -- Class : Mammalia -- Order : Proboscidea
Family : Elephantidae -- Genus : Mammuthus -- Species : M. exilis

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Dugong

Dugong

Phylum : Chordata
Class : Mammalia
Superorder : Afrotheria
Order : Sirenia
Family : Dugongidae
Genus : Dugong
Species : dugon

Length : Up to 10ft (3m)
Weight : 500-1,100lbs (226-499kg)

IUCN Status : Vulnerable

According to EDGE, the Dugong is one of the most evolutionarily diverse mammals still alive. It's closest known relative, the tragic Steller's Sea Cow, was hunted to extinction in the 18th century. Dugongs belong to the same order as the three extant Manatee species, and that order is more closely related to Aardvarks and Elephants than it is to the other aquatic mammals like Whales and Seals!

Dugongs can be found in the warm coastal waters of the Indian Ocean, stretching from Africa to Australia. They are very seldom found in freshwater. Dugongs were once hunted for their oil and meat, but are now protected through their range. Unfortunately, these large aquatic herbivores still die as the byproduct of net fishing. Because of their large size, Dugongs have very few natural predators. Only large Sharks, Orcas, and large Crocodiles actively hunt them.

Dugong

Dugongs live exclusively in water, and come to the surface only to breathe. They are able to hold their breaths
for up to six minutes at a time while they feed off of underwater grasses, and they move slowly at speeds of around 6mph (10kph).

Dugongs are typically seen alone or in very small groups, though historically there are reports of herds numbering in the hundreds. Baby Dugongs are born underwater after a one year gestation period, and the mothers push them upwards so they can take their first breaths.

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Steller's Sea Cow

The story of the Steller's Sea Cow (Hydrodamalis gigas) is a tragic one. In 1741, the ship of Dutch navigator Vitus Bering became wrecked on an island off the coast of the Kamchatka Penninsula (which would later be named Bering Island.) Bering and many of his crew members died on that island, which I suppose was a bad omen for the poor Sea Cows that were discovered there by the expedition's naturalist, Georg Steller. Steller wrote about the creatures once he and the crew were able to build a new ship from their old wreckage and leave the island. Within 27 short years, the entire species went extinct.

(Image Source)

How? Why? Bering's crew only killed and consumed one Sea Cow during their stay, but the meat was described as being delicious and of a quality that took longer to spoil than other meat. They had hides that could be used in boat making, and valuable oil that could be both eaten and burnt. Hunters began to travel to Bering Island, decimating the already minuscule population. (Estimates place the number at Steller's discovery to be around 1,500 individuals) The death of the last Steller's Sea Cow was recorded in 1768.

Steller's Sea Cows were the only Arctic members of the order Sirenia, which includes modern Manatees and Dugongs. They were also the largest; Steller recorded specimens as long as 28 feet. This dwarfs modern Sirenians which rarely grow larger than 12 feet. Steller's Sea Cows were also herbivores, which differs from most other marine mammals. They fed off of kelp and various algae. They lived in herds and were described by Steller as being monogamous.

Steller's Sea Cows were confined to arctic waters, though ancestral species within the same genus had a wider range that spread down as far as Southern California. They, and all other Sirenians, are most closely related to Hyraxes, small rodent-looking creatures. They are also distantly related to Elephants and other members of the Superorder Afrotheria.

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American Mastodon

(Image Source) 

The American Mastodon (Mammut americanum) was a large tusked mammal that inhabited North American during the late Pleistocene from about 3 million to 11,000 years ago. They stood between eight and ten feet at the shoulder and weighed around 10,000lbs. Mastodons had stocky legs and long hairs covering their bodies. They also had massive tusks, which where more straight then those of their Mammoth cousins.

American Mastodons shared their Pleistocene homes with Mammoths. Though they both belong to the order Proboscidea, Mastodons are classed in the ancient and now completely extinct family of Mammutidae, while Mammoths shared the family of modern Elephants, Elephantidae. The American Mastodon was only the last of the Mastodon line. Members of the family appeared in Africa nearly 40 million years ago, and other species existed in Europe in Asia until about 2 million years ago.

Mastodon Tooth (Image Source)

Mastodons had low, ridged teeth that demonstrate a diet based on leaf browsing. This differs from the teeth of Mammoths which were used for grazing. Another distinction between the two is that the mouth of a Mastodon contained more teeth at one time than that of a Mammoth, though they shared the same number of overall teeth in a lifetime. The conical teeth of the Mastodon are the inspiration for their name. Mastodon means "nipple tooth."

Just this past Sunday it was reported that a new skull of what is believed to be a Mastodon was found in a mine in New Mexico. It measured eight feet long. Unfortunately, the skull crumbled during the excavation process, and will now be painstakingly reassembled. Mastodon fossils are relatively common throughout the United States, especially in the Midwest. A majority of these sites contain Mastodons dated between 40,000 and 11,000 years.

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Aardvark

Orycteropus afer  is an interesting mammal. Even though they resemble anteaters, they are not actually related. Aardvarks (whose name essentially means "earth pig") are members of their own entire order, which itself is part of the superorder Afrotheria. The closest relatives of the Aarvarks are actually Hyraxes, Sengis, and Elephants!

Image Source

Aarvarks are medium sizes animals with nearly-hairless bodies and powerful claws which are used for digging at termite mounds. They also have highly specialized snouts that allow them to smell out and then lick up vast quantities of their favorite meals. Aardvarks actually do have teeth, but they grow only at the back of the jaw, have no enamel, and fall out and grow continuously throughout their lives.

Aardvarks are solitary, nocturnal animals. During the day they sleep in burrows, and they often dig completely new ones each day. Abandoned burrows can become shelter for many other smaller animals species. Females give birth to only one cub at a time, who is born pink and hairless. At about six months, any male offspring will leave and become independent. Female cubs stay with their mothers until she gives birth to another cub.

Aardvarks are not a threatened species. Their major predators include wild dogs and big cat species. Some human tribes consume Aardvark meat.

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Sengi

Also known as Elephant Shrews, Sengis are small mammals belonging to four genuses within the Macroscelididae Family. They are not actually related to true shrews all that closely, for they belong to a different Family and Order entirely. Because Elephant Shrew is a bit of a misnomer, biologists have been using the name "Sengi," which is their Bantu name. Interestingly, molecular research in recent years show that Sengis could be more closely related to the Elephant and they are to the Shrew.

Short Eared Sengis

Sengis are found only in Africa. Depending on the species, they live in savannahs and scrublands, as well as dense forests. Some species are diurnal, while others are active during both the day and night. Sengis are carnivores eat a variety of invertebrates, including worms and spiders. A few species will also supplement their invertebrate diet with fruits and other plant matter. They themselves are preyed upon by a wide variety of larger creatures, and as such, they must always be alert. Eagles, Lizards, and Snakes all hunt Sengis. When they have spotted a predator, they slap their tails on the ground as a warning signal.

Sengis mate for life, and many species breed continuously over the course of the year, though their little size is only one. While they are not a very vocal group, Sengis have exceptional sense of smell, sight, and hearing. Some will built complicated track systems throughout the undergrowth in order to both hunt and escape from predators.

Thanks to Heather for the suggestion!

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