Dynastinae or rhinoceros beetles
Dynastinae or rhinoceros beetles come in quite a few shapes and sizes, for example these below, which do not just have the one horn. In fact over 300 species of rhinoceros beetles are known.
These interesting beetles are a subfamily of the scarab beetle family (Scarabaeidae). Other common names include unicorn beetles or horn beetles. The horns are used in fighting other males during mating season, and for digging, and the body of an adult rhinoceros beetle is covered by a thick exoskeleton (word for today.....exoskeleton: is the external skeleton that supports and protects an animal's body, in contrast to the internal skeleton (endoskeleton) of, for example, a human). These animals can often be found in pet shops along and around Fish Street in Mongkok, as they have become popular pets. Get one and dive into the high stakes gambling world, as these male beetles are used for gambling fights, as the males will fight each other for females. To get them all geared up and raring to go the professionals have a small noisemaker duplicating the female's mating call. No more bets.....
Here a male covets a female (no horns) in the wild in Sai Kung Lion's nature reserve.