Members of this family are immediately recognisable by their 'free-tail' which extends beyond the end of the tail membrane, and their wrinkled upper lip (except in the larger Tadarida species) giving them a bulldog appearance.

 

Molossids can scuttle with surprising speed, forward and backward. They have conspicuous combs of curved hairs along the outer margins of the toes which appear to have a sensory function, and are perhaps also used in grooming. Pheromones also are important in their social behaviour. Each species has a distinct, strong, often aromatic scent.

 

The majority of Molossids share adaptations for crevice roosting – including stout, sturdy legs, and the specialised sensory hairs on the body and muzzle and ear margins. They often reveal their presence in daytime by strident squeaks. The wings are characteristically long and pointed – adaptations for agile, swift flight.