ABSOLUTLEY INCREDIBLE photo by Martin Le-May. Green Woodpecker and Weasel. Apparently the Woodpecker escaped. pic.twitter.com/PUt1b2Mbhs — Jason Ward (@Jayward7) March 2, 2015

Remember “weaselpecker?” That viral photo from March of a weasel “riding” on the back of a woodpecker in flight?

The dramatic encounter was likely a predatory attack gone awry, scientists said. It was also the start of trend. After several more photos of other species in similar poses became social media sensations, it became clear: 2015 was the year of animals riding animals.

It’s an odd sight to be sure, and there are always a few people who ask if animal riding photos are fake. But it’s likely this sort of thing happens all the time as animals interact with each other in the wild, it’s just that such moments are fleeting and difficult to record, and therefore rarely seen. With the proliferation of cellphones and other affordable camera technology, these bizarre moments are increasingly being documented and shared on social media, where the appetite for novel pictures is apparently insatiable. There’s even a Reddit group and a Tumblr devoted to the topic.

This year, these hitchhikers caught our attention:

An amateur photographer in a park in East London made this image of a least weasel (Mustela nivalis) clutching the back of a European green woodpecker (Picus viridis) in March. When the animals hit the ground the woodpecker escaped, likely evading the predator.

Scientists who analyzed the photo said they thought it was probably real, both from a photographic and natural history standpoint. Not only does the image look authentic, but European green woodpeckers often feed on ants on the ground, where they are vulnerable to predators like weasels.

"The natural world is filled with wonders," said David Mizejewski, a naturalist with the National Wildlife Federation, "and we have the chance of observing them firsthand if we get outside to experience them."

In July, camera trap footage from South Africa revealed a small, mongoose-like animal called a genet “riding” a black rhino. Genets have been previously recorded riding a white rhino and cape buffaloes.

Scientists think the genet gets access to insects that are stirred up by the larger animals or which parasitize them. They also get a good perch to look around and may receive some protection from predators. The big animals don’t seem to mind too much, although they apparently can get annoyed.

View Images This meeting of a crow and eagle was captured in Seabeck, Washington. Photograph by Phoo Chan, Media Drum World

A California photographer captured the moment a crow appears to be riding, or surfing on, a bald eagle in July.

Kevin McGowan, a biologist who specializes in crow behavior at the Cornell lab of Ornithology, said the sequence of images isn’t that surprising, since crows often “mob” birds of prey to drive them away from their nests. In the course of harassing them, they may appear to ride on their backs for short periods of time. Eagles seem to be fairly used to the treatment.

A photo posted by U.S. Department of the Interior (@usinterior) on Aug 3, 2015 at 4:06pm PDT

In another instance of mobbing, a visitor to a National Wildlife Refuge in the Great Plains captured the moment a red-winged blackbird was riding atop a red-tailed hawk in August.

That’s actually a common scene, scientists say, since blackbirds are among the species that routinely harass birds of prey in an attempt to drive them out of harm’s way.

View Images Surf's up? Photograph by Robyn Malcolm, Diimex.com

A bizarre photo from Australia in September shows a seal surfing on the back of a humpback whale. Scientists aren’t sure what’s behind the unusual behavior.

It’s even possible the seal was just having fun, said Michael Napier, an animal expert at the Virginia-Maryland Regional College of Veterinary Medicine.