Unsettling video has emerged from South Africa of a young elephant calf being repeatedly picked up and thrown by an older elephant bull, or adult male.

The incident was recorded in Addo Elephant National Park by nature guide Jenni Smithies and photographer Lloyd Carter during a ride past a watering hole. Their video, seen through car windows, shows the calf as it struggles to stand and is forcefully knocked to the dirt by a young male elephant that is visibly in pursuit of a sexual partner.

Eventually, the infant calf is protected by a female elephant, presumably its mother, and the male leaves.

"This is the worst case of this kind of behavior I have seen," says Joyce Poole, an expert on elephant behavior, National Geographic explorer, and co-founder of ElephantVoices, in an email. Poole has seen this kind of behavior from young males before, but rarely to this extent.

The male's aggression was likely caused by his inability to distinguish female elephant reproductive hormones, says Poole. (Watch an elephant invite a rhino to play.)

Poole explains that when female elephants are in estrous, or able to become pregnant, they give off a scent signaling their reproductive state. Males attempting to mate will singularly travel to various families and groups searching for a female giving off this scent.

The male seen in the video is likely confusing the new mother's hormonal scent with that of a female in estrous.

"The male in question is in his 20s," Poole explained in an interview. "This is the age group that is not able to discriminate between the smells of a new mother and that of a receptive female."

Older males, Poole explained, are able to distinguish scents. Male elephants reach sexual maturity at roughly 17 years of age, meaning the bull in the video was only just beginning to develop these important skills. Based on the infant calf's small size, it's likely it smelled like its mother, confusing and frustrating the bull. Male elephants reach their sexual prime at around 40 to 50 years of age.

Poole believes the female under which the infant hid, which had swollen breasts from lactating, was its mother. (Elephant calls explained.)

Elephants have longer pregnancies than most mammals, lasting nearly 22 months. After giving birth, females will typically not come into estrous for another two years.

The tuskless elephants surrounding the incident in the video were likely from the same family unit. Elephants form matriarchal societies that can be as small as a mother and a calf, or as large as 40. When babies are born, elephants will often loudly trumpet to celebrate. A possible maladaptive behavior according to Joyce, this loud trumpeting has the adverse effect of attracting passerby males.

Addo Elephant National Park reportedly has over 600 elephants, according to their website. When the park was established in 1931, they had only 11. The demand for their ivory tusks saw them nearly hunted to extinction. While populations have significantly improved, elephants still facing poaching threats in many areas.