What Is the Biggest Beetle in the World? Longest and Heaviest

Longest beetle: the Hercules beetle

If horns and jaws are included, the record for length goes to the Hercules beetle (Dynastes hercules) of Central and South America and the Lesser Antilles. Large males usually measure about 15–17 cm (6–7 in) from the tip of the long thoracic horn to the end of the wing cases, and breeders report captive-reared males slightly longer than that.

Much of this length is horn. Without it, the body measures about 50–85 mm (2–3.3 in), so the Hercules beetle is long rather than massive. Females have no horns and are much shorter. The horn is used in fights between males, explained in how strong is a Hercules beetle.

Biggest body: the titan beetle

The titan beetle (Titanus giganteus) is a longhorn beetle from the rainforests of northern South America, including the Amazon basin and the Guianas. It has the largest body of any known beetle, with the biggest specimens reaching about 17 cm (6.7 in) without any horns, and many specimens of around 15 cm (6 in).

Titan beetles are rarely seen. Adults live only a few weeks, appear mainly at night and are usually found when they fly to lights. Like other members of their subfamily, adults are thought not to feed, living on reserves built up as larvae. Their larvae have never been found with certainty, though they are believed to grow inside rotting wood. Adults can hiss when disturbed and have strong, sharp jaws, but they are not dangerous to people.

Heaviest beetles: Goliath beetles and their relatives

Weight is a different contest. The six species of Goliath beetles (genus Goliathus) from the tropical forests of Africa are among the bulkiest insects on Earth. Males measure about 6–11 cm (2.4–4.3 in) and females about 5–8 cm (2–3.1 in), and adults are thick, heavily built and boldly patterned in black, white and brown.

Fully grown Goliath beetle larvae can weigh more than 100 g (3.5 oz), and adults weigh roughly half as much as the largest larvae. The elephant and actaeon beetles (genus Megasoma), rhinoceros beetles of tropical America, are similarly heavy and are often named alongside Goliath beetles as the heaviest adult beetles. Exact weights are rarely published and vary with how well fed an individual is, so no single species holds an undisputed record.

Size comparison of the giant beetles

Why the record is hard to settle

Beetle records are surprisingly slippery. Many famous measurements come from dried museum or collectors’ specimens, which can shrink, and from captive-reared beetles fed far more than wild ones. Some measurements include horns or jaws and some do not. A beetle’s adult size is fixed when it emerges from the pupa and depends largely on how well it fed as a larva, so sizes vary hugely within each species.

Weight is even harder to compare. Adults are rarely weighed alive, and a female full of eggs weighs much more than a male of the same length. For this reason, encyclopedias usually name several “biggest beetles” by different measures rather than one winner. For giants from other insect groups, such as giant weta and stick insects, see the largest insects in the world.

Why aren’t beetles bigger?

Insects breathe through a network of air tubes called tracheae, which carry oxygen directly to their tissues. This system works well for small bodies but becomes less efficient as size increases, which is one reason why no living beetle is much larger than about 17 cm. Their hard outer skeleton, which must be shed and regrown during growth, also becomes heavy and awkward at large sizes.

Some scientists link the giant insects of the Carboniferous period, such as dragonfly relatives with wingspans of about 65–70 cm (26–28 in), to higher oxygen levels in the air at that time, although other factors were probably involved too. Beetles themselves appeared later, in the Permian, about 295 million years ago.

The biggest beetles closer to home

Europe’s biggest beetle is the European stag beetle, whose males reach about 75 mm (3 in) including their antler-like jaws. In North America, the largest beetles include the eastern Hercules beetle (Dynastes tityus), a much smaller relative of the tropical Hercules beetle, and large longhorn beetles of the genus Prionus.

At the other end of the scale, the smallest known beetles are featherwing beetles. Scydosella musawasensis measures as little as about 0.33 mm, so the largest beetles are roughly 500 times longer than the smallest.