Tag: flightless

Island Weirdness #22 – Aepyornis maximus

Along with a lot of unusual mammals, Madagascar was also home to some of the largest birds to ever exist: the giant elephant birds.

Despite being located so close to mainland Africa, these enormous flightless ratites weren’t the closest relatives of ostriches as might be expected. Instead their closest living relatives are the kiwis of New Zealand, and they must have descended from flying ancestors that reached Madagascar across the Indian Ocean sometime during the early-to-mid Cenozoic.

Aepyornis maximus was one of the biggest of these big birds, standing around 3m tall (9′10″) and weighing over 500kg (1,100 lbs). Its eggs were equally massive, up to 34cm long (1’1″) and with a circumference of over 1m (3′3), making them the largest known eggs laid by any vertebrate.

Recent studies of the shape of its brain within its skull show that it had a good sense of smell but very poor eyesight – possibly being near-blind – suggesting that much like its kiwi relatives it was highly specialized for a nocturnal lifestyle.

There were several other species of elephant bird throughout Madagascar, and at least some of them appear to have successfully survived alongside humans for quite some time. Carbon dating of eggshells suggests they were still alive around 1000 years ago, and based on historical mentions they may have persisted as late as the 1600s before finally disappearing.

Island Weirdness #04 – Gargantuavis philoinos

By far the biggest island in the Late Cretaceous European archipelago, the Ibero-Armorican island (sometimes also known as the Ibero-Occitan island) was made up of most of the Iberian Peninsula and France and was larger than modern-day Madagascar.

Around 73-71 million years ago one of the residents of this island was the aptly-named Gargantuavis – the largest known Mesozoic bird, and probably an example of island gigantism.

Although only known from a few isolated bones, it’s estimated to have been slightly larger than a modern cassowary, somewhere in the region of 2m tall (6′6″). At that size it would have also been secondarily flightless, which is surprising for a bird that was living alongside larger fast-moving theropods like abelisaurs.

Not much else is known about it due to the scarce remains, but it seems to have had a long slender neck and probably had a small head. Its hips were fairly broad, suggesting it wasn’t capable of running very fast, and it was likely a slow-moving herbivore that was a fairly rare member of its ecosystem.

Exactly where it belongs in the bird evolutionary tree is also unclear, with the best current guess being “some sort of euornithean”.

Copepteryx

Copepteryx hexeris, a plotopterid bird from the Late Oligocene of Japan (~28-23 mya).

Known from around the North Pacific rim from about 33-15 million years ago, plotopterids were flightless diving birds which used their small but powerful wings to propel themselves through the water. They were convergently similar to penguins in body shape and lifestyle, but not actually closely related to them – instead being relatives of gannets, cormorants, and anhingas.

Smaller plotopterids were about the size of modern cormorants, around 70cm long (2′4″), but the larger known genera like Copepteryx rivalled the southern giant penguins at around 1.8m (6′).

And a second species of Copepteryx known only from a single leg bone (Copepteryx titan) may have been ever bigger. Estimated at over 2m in length (6′6″), it was possibly one of the largest diving birds to have ever lived.