Hippopotamus

"River horse"
Hippopotamus gorgops
Length:
4.3 m (14 ft)
Weight:
5 tons
Time:
8,000,000-1,000,000 B.C.
Location:
Northern Red Sea Region, Eritrea; Northern District, Israel; Turkana, Kenya; Valencia, Spain; Arusha, Tanzania
This earliest form of Hippopotamus was also the largest, standing over two meters (seven feet) tall at the shoulders and outweighing most modern hippos considerably. Another key feature that set Hippopotamus gorgops apart from its modern counterparts were its eyes, which rose significantly higher from the top of the skull, making the task of minding its surroundings easier while the rest of the body was submerged.

Hippopotamus gorgops first emerged in East Africa late in the Miocene epoch and migrated to southern Europe and the modern Levant during the next epoch, the Pliocene. This development led to evolution of more varieties of hippo in Europe.
Art by Carl Buell
Hippopotamus antiquus
Length:
4.3 m (14 ft)
Weight:
3.9-4.7 tons
Time:
1,800,000-800,000 B.C.
Location:
Thuringia, Germany; Peloponnese, Greece; Tuscany, Italy; Granada, Spain; Cambridge and Yorkshire, United Kingdom
Hippopotamus antiquus, also known simply as the "European hippopotamus", retained the size of Hippopotamus gorgonops, but possessed the shorter eye stalks of modern hippos. This animal was widespread throughout European during the Pleistocene, spanning from Germany to Greece.
Art by Robert Nicholls
Hippopotamus minor
Length:
1.2 m (4 ft)
Weight:
200 kg (444 lbs)
Time:
800,000-10,000 B.C.
Location:
Lemesos, Cyprus
Island populations of Hippopotamus antiquus were also present throughout the Pleistocene Mediterranean, particularly on Sicily, Malta, and Crete. Hippopotamus minor, or the "Cypriot dwarf hippopotamus", was the smallest species of hippo ever and like other insular hippos was forced to shrink over generations on order to live off Cyprus' meager resources. Ironically, this sheep-sized herbivore was the largest animal on the island when it vanished into extinction, most likely due to over-hunting by the first humans to colonize Cyprus.
Hippopotamus lemerlei
Length:
2 m (6.5 ft)
Weight:
270 kg (600 lbs)
Time:
1,000,000 B.C.-c. 1000 A.D.
Location:
Mahajanga, Madagascar
The islandĀ  of Madagascar also played host to a population of pygmy hippos during the Pleistocene. Unlike their counterparts in the Mediterranean, however, these hippos survived well into the Holocene. Hippopotamus lemerlei is the best known of the three pygmy species known to have inhabited the island and, although about half the size of modern hippos, differed from them little in appearance and lifestyle, basking in the rivers and lakes of Madagascar. Hippopotamus madagascariensis, in contrast, seems to have been a more terrestrial species that inhabited the highlands and which displays more similarities with the pygmy hippo than the common one. The third species, Hippopotamus laloumena, is known only from a few limbs bones and a singular lower jaw and, though considerably larger than the other two species, was somewhat smaller than its modern mainland cousin.

All three species are believed to have gone extinct around the time humans first colonized Madagascar about one thousand years ago, along with the giant lemurs and the elephant bird.

Hippopotamus amphibius
Length:
3.4-5.2 m (11-17 ft)
Weight:
1.7-5 tons
Time:
2,000,000 B.C.-Present
Location:
Sub-Saharan Africa
The modern hippopotamus--Hippopotamus amphibius--is the currently the third largest land animal (behind the elephant and the white rhinoceros), as well as the heaviest living member of the artiodactyls, the family of even-toed hoofed mammals that also includes deer, sheep, goats, pigs, cows, camels, and giraffes. Hippos average slightly over three meters (ten feet) in length and and between one and two tons, though large males have been known to reach over five meters (sixteen feet) and weigh in at five tons. It is the sole surviving species of the genus Hippopotamus (the pygmy hippo belonging to another genus, Choeropsis) and is one of the most recognizable and widespread animals in Africa today.

Like its predecessors, the modern hippo spends the majority of its life in the water, wallowing in the mud most of the day to keep from dehydrating under the African sun. There, they fight for territory or mates, sleep, breed, give birth, and even defecate. Ironically, adults are incapable of swimming or floating, kick off the bottom in order to move about in deep water. Eating is one of the few things hippos do out of the water. In the cool night, they leave the water and feed on primarily on grass, consuming as much as 68 kilograms (150 lbs) of it in a single sitting. Hippos have also been known to feed on carrion and even practice cannibalism or predation, but all of these feeding behaviors are rare among them.

Despite cultural depictions of them as rotund, friendly, and comical creatures (the best example of which being the Dance of the Hours sequence in Fantasia), hippos are extremely dangerous animals. In addition to fending off crocodiles, lions, and hyenas, all of which are known to prey on their young, they are infamous for attacking humans both on land and on boats. Hippos have a bite force of up to 8,100 Newtons (rivaling that of alligators) and have mouths designed to sharpen their tusks as they grind together. They are also remarkably fast over short distances, reaching speeds of up to thirty kilometers per hour (19 mph) despite their short legs and sheer bulk.

Today, between 125,000 and 150,000 hippos live in the wild. They once lived as far north as the Nile Delta and were an important animal in ancient Egyptian culture and mythology, but thanks to loss of habitat and hunting inhabit only pockets of sub-Saharan Africa. They are, however, quite common in zoos across the world despite the cost of maintaining them.




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