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Today on Animal Fact Files we’re talking about stag beetles. Stag beetles get their common name because the males of many stag beetle species have large mandibles. Females also have mandibles, but they’re not nearly as large. Because male stag beetles joust each other in breeding matches similar to male deer butting heads during a rut, stag beetles were named after these stags. Male stag beetles are attracted to pheromones released by the females, but when two males meet one another, they’ll do whatever they can to remove their opposition. The males will attempt to throw each other from their perch - even if that perch is high in a tree. Some stag beetle males even have pockets of air in their heads and mandibles to make throwing less cumbersome; because, really, who wants to be tired when they’re getting busy. It’s usually the larger stag who gets the girl, but, in a twist of fate, smaller stag beetle males have been observed slipping past bigger, feuding opponents and enjoying some alone time with the ladies. It’s believed that stag beetle size is not necessarily a genetic trait and may come from how much a beetle ate while in its larval stage.

Stag beetle eggs are laid in wood or soil depending on the species. The female may even return to the place she emerged to lay her eggs since she knows the area is rich in food! It takes about a month for the eggs to hatch, and some species lay an average of twenty at a time. The larval stage is the longest lived of all the stag beetle stages. This is also the stage that does most of the eating. Stag beetle larvae eat leaf litter or decaying wood. These beetles actually need deadwood in order to survive, and part of their population declines can be attributed to people removing these essential habitats in stag beetle environments. Stag beetles are generally found in hardwood forests, such as those with lots of oak trees, but they can also be found on driftwood beaches and sand dunes. While living in wood or soil, stag beetle larvae may survive for years. Eventually they’ll form a cocoon chamber and pupate. When warm weather arrives in spring, adults emerge. In this stage they may only survive a few months. Predators to stag beetles include birds like blue jays and crows, reptiles like snakes and toads, and mammals like raccoons, weasels, and foxes.

Stag beetles are found worldwide and are most abundant in tropical Asia. They range in size from under an inch (2.54cm) to more than three inches (7.5cm) in length, and the males are larger than the females. In fact, in some species, such as the darwin stag beetle, a male’s mandibles may be even longer than his body! These beetles can’t just be identified by checking out their jaws. Like we mentioned, the mandibles on females are far less pronounced, and there are even some species that look like other beetles all together. For example, this stag beetle looks like a rhinoceros beetle! Usually a stag beetle can be identified, however, by checking out its antennae. Stag beetles have bends in their antennae as if they have little elbows, and they end in a sort of club shape. Also, stag beetle antennae seem to work backwards because they’re slimmer at the base than they are at the end.

Stag beetle adults may be seen during the day or night. During the day they may be sunning themselves or flying around to find a mate. At night they may congregate around artificial lights. Adult stag beetles likely only eat liquid foods like tree sap and aphid honeydew. Female stag beetles may be able to bite through wood in order to reach liquidy foods inside, but males with their cumbersome mandibles aren’t known to be able to do this. They will, however, posture as if their mandibles have some power. When faced with a predator, a stag beetle will raise its mandibles to appear larger. This might seem quite intimidating, but stag beetles are generally considered to have a harmless bite.

For more facts on stag beetles check out the links in the description. Thank you to BigGulp for today’s request! Give a thumbs up if you learned something new today, and thank you for watching Animal Fact Files.