The pink whipray (Himantura fai) is the only species of stingray know to engage in this sort of piggybacking behavior. In fact, multiples pink whiprays piggyback on others rays of the same species, and this is unexpected, elasmobranch, in general only interact when they try to eat each other.
The pink whipray is a large ray that occurs in coastal soft-sediment habitats in the Indian Ocean.
But apparently they love it, and
pink whipray
piggyback in another species. Pictures don’t lie.
The reasons for this behaviour are unknown, one possibility is that piggybacking is a predator defence strategy that allows the smaller rays to appear larger than they actually are and breaks up silhouettes on which predators can focus. There may also be some hydrodynamic or foraging advantage to the smaller rays in travelling with larger species in this manner, although this does not explain why these rays piggyback on other rays resting on the seabed or at cleaning stations.
Photo b)
Pink whiprays piggybacking on a blotched fantail ray (Taeniurops meyeni) at a cleaning station.
