The lesser mouse-eared bat has a narrow, pointed muzzle and brown-grey fur on its back. It hunts insects over warm, open grassland and other open places.
It is smaller and lighter than the related greater mouse-eared bat (Myotis myotis). Its muzzle is narrow and pointed, its back fur is brown-grey, and its ears are short and narrow.
In the French Alps, Lesser Mouse-eared Myotis share a maternity roost with the closely related Myotis myotis. Afonso and colleagues collected 250 guano samples there from May to August 2012. They obtained consistent results from 210 samples, representing 165 individuals: 140 M. myotis, 12 M. blythii, and 13 putative hybrids. The study used genetic identification to distinguish bats that look very similar.
The mix of bats changed across the five sampling dates. M. myotis dominated the first four, while the late-August sample was 39.3% M. myotis, 35.7% M. blythii, and 25% hybrids. The researchers estimated that fewer than 50 bats were present in the roost then. Their guano-based approach shows how species composition and seasonal change can be studied without capturing the animals.
An extinction-risk assessment has not been added yet.
At one French Alps maternity roost, the sampled species mix changed from May to August; M. blythii made up 35.7% of the late-August sample. The paper presents guano-based identification as a way to study mixed colonies without capturing bats.