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 hunting 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.

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.

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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.

American Mastodon

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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.

Aardvark

Orycteropus afer  is and 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!

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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.

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!