Have you ever sat by a lake on a summer evening and happened to spot those marvels of evolution? The world’s only flying mammals, bats make their home on every continent (except for Antarctica), and account for one-fifth of all mammal species living on the planet.
The Pallas’s long-tongued bat
At the Biodôme we’re fortunate to have three species of bat: the Jamaican fruit-eating bat, the Seba’s short-tailed bat and the Pallas’s long-tongued bat. This last one is a small nectar-feeding species – and possesses the fastest metabolism ever recorded in a mammal!
The hovering that bats do requires enormous energy. They depend on nectar found at the bottom of flowers to fuel close to 80 percent of their metabolism needed for that activity. While they feed, they pollinate the flowers.
Bats are incapable of detecting colors, but they can perceive ultra-violets, which among other things helps them identify white flowers. It’s been observed that flowers pollinated by bats have particularly large male reproductive organs, which produce seven times more pollen than flowers that attract hummingbirds.
Lonchophylla robusta, or the orange nectar bat, which is found in South America and Central America, drinks the equivalent of 150 percent of its own weight every night, while its tongue hardly seems to move when it feeds. The tip of it remains submerged in the flower. The tongue has two open grooves extending along the sides. Tiny pump-shaped muscles push the nectar up those grooves. Other nectar-feeding bats rather have absorbent taste buds that act like the hairs of a rag.
A world record
Anoura fistulata (Ecuador, Bolivia, Colombia and Peru), or the tube-lipped nectar bat, has the longest tongue of all mammals relative to its body size. Its 85 mm tongue is 1.5 times longer than its body and has its base in the bat’s ribcage. It passes through the neck, between the heart and the breastbone.
This bat pollinates just one species of flower: Centropogon nigricans, the first known example of a flower pollinated by a single species of bat.
Co-evolution of the bat and plants
The deserts and arid regions of the Americas are unique in the world. Their dominant plants, such as cactus and agaves, depend on nectar-feeding bats to reproduce. No other desert can claim such examples of mutualism. Much research nevertheless remains to be done for these co-evolutions to be fully understood. More fascinating material awaits!