Gruber's team of researchers work day and night. In this episode they record a shark's vital statistics while it's in a state of tonic immobility. Before releasing it, they take a DNA sample. Enjoy!

At times, Doc Gruber's research requires the team to dive right into shark-infested waters! Their line of work certainly isn't for the faint of heart! Enjoy.

Nathalie and Jim get up close and personal with tiger and lemon sharks, trying to get the best footage while taking care not to disturb or excite the dangerous animals.

The team's divers conclude their filming and come back to the surface unharmed. We learn more about current developments in the prevention of shark attacks.

In this episode, Doc Gruber and a colleague are testing a shark repellent. If effective, it could help save the lives of divers, swimmers and surfers all over the world.

Here's some more stunning underwater footage. This time it's hammerhead sharks and stingrays, a wahoo and some striped eels, all filmed near the Cocos Island in the Caribbean. Take a look!

Samuel Gruber's team films white-tipped sharks and barracuda feeding at night off Cocos Island. Enjoy!

The great white shark and killer whale are both infamous marine predators. Normally they leave each other alone, but one day, biologists off the cost of California witness something unprecedented.

Several boats converge near the largest of the Farallon Islands when killer whales are spotted. But what they think is a young killer whale turns out to be a great white shark.

Orcas are at the top of the food chain, but it is unprecedented that they would go after a great white shark. From the boat, whale watchers and experts alike are shocked by what they see.

Why would a killer whale go after a great white shark? Enter Alisa Schulman-Janiger, a biologist who is very familiar with the different families of killer whales off the coast of California.

So if an orca attacking a shark is so rare, how do they usually behave? In this segment, we learn about how orcas around the world live and hunt.

Some orcas do prey on sharks, but how do they do it? Researchers also have to catch sharks occasionally, and there is a particular technique that they use.

The phenomenon of tonic immobility helps researchers study sharks, but does it also help orcas hunt and kill them?

Here we see a simulation of how the attack happened, and find out what effect it had on the population of great white sharks around the Farallon Islands.