Killer whales go on 'unprecedented' killing spree in Monterey Bay

Photographers snapped some amazing pictures of killer whales and humpbacks while watching off the coast of Monterey, Calif. in April 2017. Photographers snapped some amazing pictures of killer whales and humpbacks while watching off the coast of Monterey, Calif. in April 2017. Photo: Bernardo Alps/Monterey Bay Whale Watch Photo: Bernardo Alps/Monterey Bay Whale Watch Image 1 of / 45 Caption Close Killer whales go on 'unprecedented' killing spree in Monterey Bay 1 / 45 Back to Gallery

A week of insane whale sightings in Monterey Bay got even crazier Wednesday when a pod of nine killer whales attacked a gray whale calf right in front of a whale watching tour boat.

This is the fourth kill in seven days for the group of orcas. That's one kill every other day since last Thursday by the same nine killer whales (with a few others joining occasionally). Nancy Black, a marine biologist with Monterey Bay Whale Watch who has been studying these whales for decades, called the frequency of the pod's killings "remarkable" and "unprecedented."

"This has never happened in my thirty years," Black told SFGATE. "Just to witness that out in nature when you usually see that kind of thing on television is really spectacular."

The back-to-back killings, as sad as they may seem, have translated into a spectacular show of nature for sightseers.

Black explained the hunt can take anywhere from an hour to a few hours, as the mother gray whale desperately tries to protect her calf, using her tail to fight back and rolling over belly-up with the calf on top.

The whales' most recent killing on Wednesday (shown in the video below) was more efficient than usual, taking about twenty minutes. The video shows the mother splashing and trying to protect her offspring, but Black thinks this mother and calf may have been skinnier than others, and therefore weaker.

"This was almost a record for how quick the killer whales attacked the mother and calf," she said.

To make things even more exciting, humpback whales have come to Monterey Bay early this year. Black estimates there are between 60 and 70 in the area now, and they're known to get involved in the killer whales' hunts.

"Humpbacks like to interfere with the killer whales for some strange reason," Black said. "They seem to want to protect the prey." She added that humpback whales will sometimes charge over to the site of the kill and blow their trumpets, trying to get the killer whales to back off.

MORE VIDEO: Whale watching in Monterey is crazy right now

Monterey Bay is a prime hunting ground for orcas as gray whales make their way up the California coast.

Black explained, "Mothers and calves are last to migrate because they stay in Mexico longer so their calves can grow up and gain weight before they make that long migration."

The mothers and their calves typically remain fairly close to the shore on their migration northward because it's safer and food is more abundant. However, as they come across Monterey Bay, the geography makes it harder for them to stay close to the coast.

The killer whales are familiar with the gray whales' migratory habits and are often wait in the bay for young, vulnerable gray whale calves to cross. This year, the arrival of the gray whales came a few weeks late (the water was cooler in Mexico, so the whales had to migrate farther south than usual), which meant lots of hungry killer whales were waiting.

"These nine whales must be very full yet continue to eat," Black said. "I expect they will become even more social in upcoming days as they [usually] do after stuffing themselves."

Despite days of feasting, the killer whales show no signs of slowing down.

"You'd think they'd already be full," Black said.

Apparently, not.