It's about one-and-one-tenth times as heavy as a Hippopotamus
In other words, 4,000 kilograms is 1.07 times the weight of a Hippopotamus, and the weight of a Hippopotamus is 0.9350 times that amount.(Hippopotamus amphibius) (adult, male)
The average weight of an adult male hippopotamus ranges from 3,000 to 4,500 kg. Appearances to the contrary, adult hippos cannot swim or float in water; they actually move by leaping and walking across lake bottoms at about 8 kph (5 mph).
It's about one-and-a-half times as heavy as The Tongue of a Blue Whale
In other words, the weight of The Tongue of a Blue Whale is 0.670 times 4,000 kilograms.(Balaenoptera musculus) (adult)
The tongue of a Blue Whale can weigh up to 2,700 kilograms. Despite their tremendous size, blue whales feed almost exclusively on tiny crustaceans called krill and cannot swallow anything much larger than a beach ball.
It's about two-thirds as heavy as an Elephant
In other words, the weight of an Elephant is 1.50 times 4,000 kilograms.(for African bush elephant, Loxodonta africana) (Adult, bull)
A bull African bush elephant weighs about 6,100 kg. Among African elephants, both males and females have tusks (whereas female Asian elephants, Elephas maximus, do not have tusks) which can grow to 3 m (10 ft) and typically weigh about 4,000 kg
It's about three-fifths as heavy as a Tyrannosaurus rex
In other words, 4,000 kilograms is 0.630 times the weight of a Tyrannosaurus rex, and the weight of a Tyrannosaurus rex is 1.60 times that amount.(for FMNH PR2081, a.k.a. "Sue") (a.k.a. Tyrannosaurus, a.k.a. T-Rex) (estimated live weight)
The notable Tyrannosaurus specimen housed at the Field Museum of Natural History in Chicago, Illinois, "Sue," is estimated to have weighed about 6,400 kilograms while alive. A renowned predator in popular culture, the teeth of tyrannosaurus rex were up to 33.02 cm (13 in) long.
It's about one-and-nine-tenths times as heavy as a Rhinoceros
In other words, the weight of a Rhinoceros is 0.530 times 4,000 kilograms.(for Black rhinoceros, Diceros bicornis) (Adult, male)
An adult black rhinoceros weighs between 1,400 and 2,800 kg. Rhinoceros are extremely aggressive — nearly one of every two males will die as a result of fighting with other rhinoceros.
It's about two times as heavy as a Giraffe
In other words, 4,000 kilograms is 2.07 times the weight of a Giraffe, and the weight of a Giraffe is 0.4830 times that amount.(Giraffa camelopardalis reticulata) (adult, male, maximum of range)
An adult, male giraffe can weigh up to 1,930 kg. Reaching 5.5 m (18 ft) in height by adulthood, giraffe calves can grow as much as 3 cm (1 in) per day.
It's about two-and-a-half times as heavy as a Car