The lesser long-nosed bat spends the day roosting in abandoned mines and caves in vast, densely packed colonies, that may contain between 1,000 and 100,000 individuals (6). About an hour after sunset, this enormous group of bats emerges to start foraging for nectar, pollen and fruit (2) (6).
The lesser long-nosed bat favours nectar and pollen from agave flowers, and nectar, pollen and fruit from cacti, especially saguaro (Cereus giganteus) and organ-pipe (Stenocereus thurberi) cacti (6). Landing on the flower, or hovering next to it (1), the lesser long-nosed bat uses its long, specialised tongue to lap up the nectar. As it feeds from the flower, its body becomes covered with pollen. The bat uses its feet to groom the pollen from the fur and then ingests the pollen as it licks its claws clean (6). When feeding, the lesser long-nosed bat frequently transfers pollen from one plant to another, and thus is a very important pollinator of cacti and agaves. Through its fruit feeding, it also assists in seed dispersal (6). Insects have also been found in the stomachs of lesser long-nosed bats, although these may have just been accidentally consumed when feeding on nectar (6).
The female lesser long-nosed bat gives birth to a single young each year, after a gestation period of about six months (6). The birth of the young typically coincides with peaks in flower and fruit availability, which varies in timing throughout its range (6).
The young has almost fully-sized feet at birth, enabling it to hang from the roost ceiling while the adults are forgaing. It feeds on its mother’s milk for four to eight weeks (6). The young can fly at around four weeks of age, and begin leaving the roost on evening flights at six to seven weeks (5).
The most northerly populations of the lesser long-nosed bat migrate each year from the south-western United States to northern and central Mexico, following the flowering season of plants such as agaves (6). They leave in September, after breeding, and return in May (2).