The link between birds and dinosaurs has become increasingly apparent over the years. Although the scientific community is pretty settled on this evolutionary link, debate is sure to continue among the public regarding where this group of animals came from. I'm not here to start an argument about evolution. But, I dare you to get face-to-face with this monstrous bird and not shudder in terror, because you are looking a freaking dinosaur in the eye.
This is a cassowary. No, this is not actually a dinosaur. But, like all birds, it has an ancestral link to the dinosaurs. Whenever I see birds like this, I have a hard time denying that there is an evolutionary link between our avian friends and the “terrible lizards” of millions of years ago.
When I come across birds that look like fuzzy rodents, however, the physical kinship between dinos and birds becomes a tad less obvious. When I see this kiwi, I have a bit of a hard time I’m even looking at a bird and not some sort of long-nosed gopher.
Look how fuzzy!
Not only is the kiwi a bird (and most decidedly not a gopher), it is actually pretty closely related to that terrifying dino-bird, the cassowary. Both are part of a monophyletic (from the same ancestral lineage) group of flightless birds called the ratites. The word ratite comes from the Latin word for “raft,” and describes birds that have no keel on their sternum – a.k.a., no place in their chest for wing muscles to attach. Even if they had proper wings (which they don’t), this lack of a keel would prevent them from flying.
This group of birds also includes ostriches, emus, and rheas – all giant flightless birds found predominantly in the southern hemisphere. Modern science views these birds as descendants of early flying birds who evolved flightlessness and bigger bodies than their flighted counterparts. The term “ratite” doesn’t apply to all flightless birds – for example, you’d never see a penguin lumped into this group. Why? Because they are more recently descended from birds of flight, and they do have a keel in which their wing muscles are attached. If penguins were to suddenly sprout well-developed, powerful wings, they could have the ability to fly. Ratites, however, aren’t so lucky in this department.
I believe!
Kiwis, although much more similar in stature to the penguins than the ostriches, are still classified as ratites. In fact, some sources believe that the kiwi’s ancestors may have been giant birds themselves, making kiwis a tiny version of a giant bird – which itself was a large version of a smaller bird at one point in its evolutionary history.
Many studies of ratite evolutionary history have identified these birds as primitive descendants of bipedal (two-footed) dinosaurs, branching off before other groups of smaller, flighted birds did. Now, thanks to the advent of DNA-based molecular data, older theories are being tested and ratites are still trying to find their exact spot in the evolutionary tree. But whether or not these birds are closer to sparrows or velociraptors, I still find myself fascinated with their striking resemblance to dinosaurs. Because if Jurassic Park came true and dinosaurs started coming out of the woodwork, I strongly suspect they would look something like this cassowary:
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