Nick Garbutt / Masai Giraffes (Giraffa camelopardalis) on open plains browsing Whistling Thorn Acacia (Acacia drepanolobium). Slopes of the Ngorongoro Highlands with the Serengeti Plains beyond, Tanzania. (Digitally...

Gerry Ellis / Whistling Thorn (Acacia drepanolobium) tree over savannah, Masai Mara National Reserve, Kenya

Mitsuaki Iwago / Masai Giraffe (Giraffa tippelskirchi) feeding on Whistling Thorn (Acacia drepanolobium) acacia tree, Serengeti National Park, Tanzania

Gerry Ellis / Whistling Thorn (Acacia drepanolobium) and moon, Amboseli National Park, Kenya

Mitsuaki Iwago / Whistling Thorn (Acacia drepanolobium) tree on savannah at sunset, Serengeti

Shin Yoshino / Whistling Thorn (Acacia drepanolobium) trees, Masai Mara National Reserve, Kenya

Mark Moffett / Ant (Pseudomyrmex sp) group drink nectar from Whistling Thorn (Acacia drepanolobium) acacia tree and protect the tree from leaf eating enemies ensuring mutual survival, Costa Rica

Mark Moffett / Ant (Pseudomyrmex sp) gathers carrot-like growths from Whistling Thorn (Acacia drepanolobium) acacia tree for delivery to larva in nest, in return for baby food, ant protects Acacia, Costa Rica

Mark Moffett / Ant (Pseudomyrmex sp) gathers carrot-like growths from Whistling Thorn (Acacia drepanolobium) acacia for delivery to larva in nest, in return for baby food Ant protects Acacia, Costa Rica

Ingo Arndt / Sunrise in the Masai Mara National Reserve, with Whistling Thorn (Acacia drepanolobium) tree in picture, Kenya

Ingo Arndt / Whistling thorn tree (Acacia drepanolobium) in open Savanna Grassland under storm clouds, Masai Mara National Reserve, Kenya

Cheryl-Samantha Owen / Three Eurasian bee-eaters (Merops apiaster) sitting on the branch of a whistling thorn acacia tree (Acacia drepanolobium) Grumeti Reserve, Northern Tanzania.