It's about nine-tenths as heavy as an Elephant.
In other words, the weight of an Elephant is 1.10 times 6 tons.(for African bush elephant, Loxodonta africana) (Adult, bull)
A bull African bush elephant weighs about 6.70 tons. 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 weigh up to 0.099 tons.
It's about nine-tenths as heavy as a Tyrannosaurus rex.
In other words, 6 tons is 0.850 times the weight of a Tyrannosaurus rex, and the weight of a Tyrannosaurus rex is 1.20 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 7.10 tons 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-two-fifths times as heavy as a Hippopotamus.
In other words, 6 tons is 1.450 times the weight of a Hippopotamus, and the weight of a Hippopotamus is 0.690 times that amount.(Hippopotamus amphibius) (adult, male)
The average weight of an adult male hippopotamus ranges from 4.130 tons. 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 two times as heavy as The Tongue of a Blue Whale.
In other words, the weight of The Tongue of a Blue Whale is 0.50 times 6 tons.(Balaenoptera musculus) (adult)
The tongue of a Blue Whale can weigh up to 3 tons. 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 half as heavy as an Anchor of a Cruise Ship.
In other words, 6 tons is 0.4820 times the weight of an Anchor of a Cruise Ship, and the weight of an Anchor of a Cruise Ship is 2.07 times that amount.(for QE2 forward anchor, a.k.a. RMS Queen Elizabeth 2)
Each of the forward anchors of the RMS Queen Elizabeth 2 weighs 12.50 tons. The anchor of the QE2 now sits in front of the Holyrood Church in Southampton, England, United Kingdom, along a pedestrian tourist route known as "the QE2 mile."
It's about two times as heavy as a Giraffe.
In other words, 6 tons is 2.20 times the weight of a Giraffe, and the weight of a Giraffe is 0.450 times that amount.(Giraffa camelopardalis reticulata) (adult, male)
An adult, male giraffe weighs an average of 2.80 tons. 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 Rhinoceros.
In other words, the weight of a Rhinoceros is 0.380 times 6 tons.(for Black rhinoceros, Diceros bicornis) (Adult, male)
An adult black rhinoceros weighs between 2.30 tons. Rhinoceros are extremely aggressive — nearly one of every two males will die as a result of fighting with other rhinoceros.