Largest Carnivore - Southern Elephant Seal
Weight: 2.2 – 5 tonnes (2.38 – 5.5 tons)
Length: 4.2 - 6 m (14 - 20 ft)
Southern elephant seals are the largest species within the Order Carnivora. Male southern elephant seals weigh four to five times that of females. Prior to the inclusion of the southern elephant seal and its relatives in the Carnivora (they had previously belonged to the Order Pinnepedia) the largest carnivore was the polar bear. Other large carnivores include brown bears and Siberian tigers.
Largest Cetacean - Blue Whale
Weight: 110 - 160 tonnes (110 - 176 tons)
Length: 20 - 30 m (66 - 98 ft)
The blue whale is the largest member of the Order Cetacea. But its accolades don't stop there. The blue whale is also the largest animal alive today and is perhaps the largest animal ever to have lived. Blue whales produce vocalizations at volumes in excess of 180 decibels, earning them the title of the loudest animal on the planet. The fin whale comes in a close second in size to the blue whale.
Largest Even-Toed Ungulate - Hippopotamus
Weight: 1.4 - 1.5 tonnes (1.38 - 1.5 tons)
Length: 2.7 m (9 ft)
The hippopotamus is the heaviest of the even-toed ungulates. The giraffe is another notably large even-toed ungulate. Giraffes, though significantly lighter than hippoptamuses, are the tallest of all living land animals. Members of the even-toed ungulates that are eclipsed by the hippopotomasus' bulk and dwarfed by the giraffe's height include camels, pigs, deer, pronghorn, cattle, and antelope.
Largest Lagomorph - European Hare
Weight: 3 - 6.5 kg (6.6 - 11 lbs)
Length: 680 mm (26.77 in)
After elephant seals, blue whales, and hippos, a hare can't possibly seem that big but even the smaller groups of mammals have their larger breeds. Of all the members of the Order Lagomorpha, the largest is the European hare. It may not be the Were-Rabbit, but the European hare does tip the scale at a respectable bulk.
Largest Marsupial - Red Kangaroo
Weight: 25 - 90 kg (55 - 200 lbs)
Length (body): 1 - 1.6 m (3.25 - 5.25 ft)
Length (tail): 75 - 120 cm (30 - 47 in)
The red kangaroo is the largest of the marsupials. Male red kangaroos can be more than twice the weight of females. The sexes can be distinguished by their coat color (males are a rusty red color while females are blue-grey).
Largest Odd-Toed Ungulate - White Rhinoceros
Weight: 2.33 tonnes (2.5 tons)
Length: 3.7 - 4 m (12 - 13 ft)
The odd-toed ungulates include horses, zebras, asses, tapirs, and rhinoceroses. Of all the species in these groups, the white rhinoceros is the largest. White rhinos have two horns, a short neck and hump on the back of the neck. Despite their name, white rhino are not white but are instead brown to slate grey. White rhinos inhabit grassy, open plains and savanna type habiats that also have some shrubs and trees. The white rhinoceros and the hippopotamus rival each other as being the largest land animal after elephants.
Largest Primate - Eastern Lowland Gorilla
Weight: 225 kg (500 lb)
Length: 1.83 m (6 ft)
The eastern lowland gorilla is the largest living primate. Eastern lowland gorillas are occassionally exhibited in zoos, so records of animal weights have been collected. The largest known eastern lowland gorilla, Phil, resided at the St. Louis Zoo from 1941 to 1958. Phil weighed 388 kg and was 180 cm tall.
Largest Proboscid - African Elephant
Weight: 4 - 7 tonnes (4.5 - 7.8 tons)
Length: 4 - 5 m (13 - 16 ft)
The African elephant is the largest of the proboscids. Of course, there are only two species of proboscids—the other species being the Asian elephant—so being the bigger of two species many not sound like much of an achievement. But not only are African elephants the largest proboscid, they are also the largest land animal. Asian elephants are the second largest land animal, followed by the white rhinoceros and hippopotamus.
Largest Rodent - Capybara
Weight: 35 - 66 kg (77 - 145 lb)
Length: 1.1 - 1.3 m (3.5 - 4.3 ft)
The capybara is the world's largest rodent. This semi-aquatic mammal lives throughout much of South America including Colombia, Ecuador, Bolivia, Venezuela, Brazil, Argentina, Guyana, Uruguay, Peru, Paraguay, Suriname, Frenh Guyana. It inhabits dense forests that are close to lakes, ponds, rivers, and swamps. Agouti, chinchillas, coyphillas and guinea pigs are the capybara's closest living kin. Capybaras have a large body, coarse fur, and partially webbed feet. The largest known rodent ever to have lived is the now extinct Josephoartigasia monesi.
Largest Sirenian - West Indian Manatee
Weight: 200 - 600 kg (440 - 1320 lb)
Length: 2.5 - 4.5 m (8.3 - 15 ft)
The West Indian manatee is the largest of all sirenians, a group of fully-aquatic marine mammals that includes the dugong and three species of manatees. The West Indian manatee includes two subspeces, the Florida Manatee and the Caribbean Manatee. The West Indian manatee was once dwarfed by another sirenian species, the Steller's sea cow. Formerly abundant in the North Pacific, the Stellar's sea cow was hunted to extinction by 1768, only 27 years after the species had been discovered by Europeans.