A heart-wrenching video posted to Twitter on Monday captured a mother dolphin refusing to let go of her recently deceased calf in Indian Shores.

The video was shared by See Through Canoe, a St. Petersburg-based company that manufactures transparent canoes.

“Mother #dolphin not ready to let go of her dead calf and pushing it through the Intracoastal waterway. It’s hard to say for sure without examination, but the calf may have been hit by a boat. Please don’t assume that because #dolphins are fast that you won’t hit them,” the company said in the tweet.

A second adult dolphin can be seen in the video helping the mother push the calf to the surface when it begins to sink in the intracoastal waters, just south of Clearwater Beach.

While the video is heartbreaking, the mother dolphin’s actions should be far from surprising — evidence of grief-like behavior in animals, particularly among aquatic mammals, has been documented in numerous studies over the years, including in a paper in the journal Zoology.

The paper says that dolphins were 18 times more likely than others to exhibit this type of behavior, often holding onto the body of a calf or juvenile long after death.

“It was really hard to watch,” See Through Canoe tweeted under the video. “That image is going to be stuck in my head for a while. I saw a lot of boaters almost run over dolphin this past holiday weekend so I’m not real surprised. Just saddened.”