"It's the biggest battle in nature, right here in your own backyard," says marine biologist Nancy Black speaking with the Monterey Herald, and she's talking about orca killer whales hunting for gray whale calves traveling alongside their mothers. It's happening right now in Monterey Bay, and the video above from Chris' Fishing and Whale Watching shows pairs and pods of killer whales roaming the bay, actively hunting for their next meal.

The whales are on their way to Alaska for the summer from Mexico, where they'll be dining on all kinds of fish and marine life, and they're stopping off in Monterey Bay in especially large numbers this year. The Chronicle says there are an estimated 20 orcas in and around the area as of this month.

The Bay is known as one of the most visible (to humans) hunting grounds for the orcas, because it's known to have deep water where the gray whales must cross, outside their usual comfort zone in protected shallow waters along the coast. It can take 45 minutes or more for the whales to kill a calf, and as Black says, they have highly coordinated hunts. "The killer whales get really excited when they are feeding on the gray whale. When they are hunting it, there are lots of underwater calls and communication calls."

As CBS 5 notes, biologists are curious to see if there's an uptick in the picking off of baby gray whales given the decline in the sea lion population, which typically is a primary food source for the orcas.

Also popular with the orcas, as Black tells the Herald, are schools of common dolphins who have moved into the area from Southern California seeking colder waters. "The killer whales are doing like anybody else and trying to make ends meet," she says, and with schools of 1,000 to 5,000 dolphins hanging around, she's already seen eight attacks on them by orcas this season.

Previously: Video: Humpback Whale Leaps Out Of Water, Onto Kayakers