Hummingbirds aren’t just incredible stunt pilots: they’re also naturally gifted engineers. The huge fuel demands of their energetic lifestyle mean they have evolved tongues which work like eye droppers, pumping the nectar straight out of plants.
Dr Alejandro Rico-Guevara and his group from the University of Connecticut travelled all over South America with slow-motion cameras and captured incredible footage showing how one of nature’s most remarkable birds gets its energy. Hummingbirds are well known for high speed manoeuvres and incredible aerobatics, which they achieve on a diet consisting almost entirely of nectar. Whilst nectar is full of energy, the effort hummingbirds need to go to access it means that when they find it, they need to drink as much as possible as fast as possible.
Biologists previously knew that hummingbird tongues had grooves running down them, and suspected that these were there to help the bird with their astonishingly fast drinking, but how hummingbirds put them to use was unknown. A new paper, published in Proceedings B has shown that when the tongue is inserted into the flower, the grooves are kept tightly closed. Once the tip of the tongue reaches the nectar pool at the base of the flower, the grooves spring open into tubes. The motion of opening the grooves creates enough suction to pull the nectar out of the flower and on to the bird’s tongue, which it pulls back into its mouth to drink.
The speed at which this process works means a hummingbird can get a full mouthful of nectar in about 10 thousandths of a second, which you can see in one of their slow-motion videos. When the bird pulls its tongue back into its mouth, it squeezes the nectar back out of the grooves to drink it: which reset the grooves back down to their flattened shape, ready to suck more nectar up in the next sip.
This new research across a whole range of hummingbird species puts to bed a 100 year old theory that the birds tongues behaved like long, thin sponges, and shows that when it comes to being speedy, hummingbirds have evolved all the best tricks.