Mantahawk
From Equestripedia, the Archives of Equestria!
A Mantahawk is a species of what appears to be of Avian and Aquatic origin.
Biology and behavior
Mantahawk's appear to be aquatic-avian like creatures who seem to inhabit the Equestrian Seas. They are incredibly large creatures, able to fit more than six ponies and a baby dragon on their backs and still have plenty of room to spare. In addition to their size, Mantahawks appear to be gentle and kind-hearted beings as one was shown to be affectionate towards Fluttershy and watched her with warm eyes.
History
The history of the Mantahawks is largely unknown. Jewel arranged for a Mantahawk to guide Fluttershy and her friends back home after the Salty Sea Mare was stuck in the middle of the ocean, and it did so with a warm, caring smile.