In Hell's Aquarium, even the normal fish were dangerous. Case in point, Xiphactinus, a strange predatory fish with a face like a bulldog. These fish patrolled the Cretaceous oceans in search of prey, be it small fish or even 6 foot birds. If you were to dive into the Cretaceous sea, there would be a good chance you would see a Xiphactinus; and there's an even greater chance it would be the last thing you'd ever see.

Basic info

Meaning of name: Xiphactinus means "sword-ray".

Time of existence: Xiphactinus lived in the early to late Cretaceous, 112 million to 66 million years ago.

Diet: Xiphactinus was a voracious predator, feeding on many different creatures that shared the sea with it, including fish, birds, and even pterosaurs, which they would catch by leaping out of the water.

A Xiphactinus attempts to catch a Pteranodon

Threats: Xiphactinus was still viable prey for other creatures in the ocean, like Tylosaurus.

Length: Xiphactinus grew to 16.7 feet long.

Attributes: Xiphactinus had extremely sharp teeth used to catch and wound its prey, as well as hold them as it swallowed them whole. They also had gills that they used to regulate oxygen. Xiphactinus were also quite fast, and able to leap out of the water. They also had quite large eyes that most likely allowed them to see in the murky depths. They also most likely used ambush tactics to hunt.

A Xiphactinus swimming in an attempt to ambush

Appearances in the Walking with... series

Chased by Sea Monsters

Episode 1-Dangerous Seas

After Nigel jumps into the ocean to escape a Tarbosaurus, a Xiphactinus swims in front of him in the opening.

Xiphactinus in the intro

Xiphactinus is also seen in the opening synopsis, representing the most dangerous sea. A small group of them is seen swimming before one is attacked by a Tylosaurus.

Episode 3-To Hell...and Back?

Xiphactinus first appears in the opening recap, where it is seen swimming, and another is shown being attacked by a Tylosaurus. Xiphactinus also plays a recurring role in the Cretaceous segment of the episode, roaming Hell's Aquarium. Xiphactinus first appears during a large feeding frenzy, where a few of them are seen surrounding a large blood patch while Nigel investigates using a periscope. When he sees the Xiphactinus, he describes it by saying "if the Devil kept fish, this would be one of them". As they swim, one big Xiphactinus swims right up to the periscope, with a Hesperornis in its jaws and swallowing it whole. Later, as Nigel and the crew move to deeper waters, a Xiphactinus can be seen leaping out of the water to attempt to catch a Pteranodon, though it fails. Xiphactinus makes a final appearance when Nigel dives with an Archelon, swimming under him in an attempt to ambush him. Luckily, it fails, and Nigel scrambles onto a lifeboat.

A Xiphactinus eating a Hesperornis