Rhinoceros Beetle

Extremely strong relative to its size, though the famous numbers need context. Laboratory studies have measured rhinoceros beetles pulling sledges and carrying weights equivalent to many times their own body mass — figures of 30 to 100 times are well supported for short efforts, and the widely repeated "850 times its own weight" comes from an experiment measuring the maximum a beetle could bear on its back before collapsing. This is possible because muscle power scales with cross-sectional area while body weight scales with volume, so as an animal gets smaller its relative strength goes up. A beetle the size of a person would not be able to lift a tank; the ratio only works at insect scale. Even so, among animals of similar size, rhinoceros beetles are near the top for load-carrying.

Fighting other males, almost entirely. Rivals meet on tree branches or trunks at sites where sap is flowing or a female is present, and they duel by trying to get their horns underneath the opponent's body, pinch him between the head horn and thoracic horn, and then lift, twist, and pry him loose so he falls or retreats. The winner gets the feeding site and the mating opportunity. The horns are not used against predators and are not weapons in the cutting sense — they are levers and clamps. Females, which do not fight over resources, have no horns at all.

Surprisingly little, according to research on the Japanese rhinoceros beetle. Scientists expected a long head horn to unbalance the beetle in flight, slow its running, or make it more conspicuous to predators, all of which would limit how large the horn could evolve. Instead they found the horn is lightweight for its length, sits close to the body's centre of mass, and imposes no measurable penalty on flight performance, sprint speed, or survival in the field. Because the weapon is nearly "free" to carry, sexual selection has been able to drive it to the exaggerated sizes seen in the largest species.

Keeping beetles is a long-established part of childhood in Japan and several other East Asian countries, a bit like keeping caterpillars or stick insects elsewhere but on a much larger cultural scale. Native species such as the Japanese rhinoceros beetle (kabutomushi) and Japanese stag beetle (kuwagata) are collected in summer, bought live in department stores, pet shops, and even vending machines, kept in ventilated cases with beetle jelly and rotting-wood substrate for the larvae, and sometimes matched against each other in gentle pushing contests. Large exotic species like Hercules and Atlas beetles command high prices among adult collectors. The hobby has driven a substantial trade in live beetles and their grubs.