[1] The beaver beetle has various modifications to suit its ectoparasitic mode of life.

It resembles a flea or a louse in appearance and the family Platypsyllidae was originally placed in the flea order Siphonaptera,[5][6] and one taxonomist treated it as a unique example of a new order of insects.

The larvae are also ectoparasitic on beavers and have hooks on the three thoracic segments which enable it to cling to its host.

[1] Besides the North American beaver (Castor canadensis) and the Eurasian beaver (Castor fiber), the only other host on which this beetle has been found is the North American river otter (Lontra canadensis), and this was only on one occasion.

Both adult beetles and larvae feed on epidermal tissue, and also perhaps on skin secretions and liquids oozing from wounds.