Mystacinidae – New Zealand short-tailed bats

Containing only two species (one which might already be extinct), this is the family of New Zealand short-tailed bats

This family is characterized by several unique features that set it apart from other bat species, including their short tails, the ability to conceal their wings, and a lifestyle that is more terrestrial than aerial compared to their counterparts.

One of the most notable behaviors of Mystacinidae bats is their preference for foraging on the ground. This terrestrial foraging strategy is quite rare among bats, as most species are predominantly aerial. The Mystacinidae bats use their wings for support as they scuttle along the forest floor in search of food. This behavior is believed to be an adaptation to the scarcity of aerial insects in New Zealand, prompting these bats to exploit the rich ground-dwelling invertebrate fauna instead. Their ability to hide their wings is not an indication of shyness to fly but rather a functional adaptation that allows them to navigate through dense underbrush and narrow spaces without damaging their delicate wing membranes.

Unlike other bat species in New Zealand, they do not engage in prolonged hibernation. This is particularly interesting given the temperate climate of New Zealand, which can offer limited food resources during the colder months. Instead, these bats have been observed actively foraging on relatively warm winter nights, taking advantage of the seasonal availability of prey. Their diet is diverse and includes resting and flying arthropods, small amounts of fruit, nectar, and pollen. They are also known to forage on carrion, displaying an opportunistic feeding behavior that likely contributes to their survival in various environments.

Mystacinidae bats are also referred to as “thumbless bats,” though this is somewhat misleading. Their thumbs are not absent but are instead folded into their wing structure, a trait that is unique among bats. This adaptation may aid in their terrestrial locomotion and possibly in manipulating food items. Their fur is typically dark gray, providing camouflage in the shadowy forest environments where they forage and roost.