Thresher Shark

0:00:02 > 0:00:06My name's Steve Backshall. Self-confessed shark-obsessed.

0:00:06 > 0:00:08This is Shark Bites.

0:00:10 > 0:00:13This time, we meet the most striking shark of all...

0:00:13 > 0:00:15..the thresher shark.

0:00:15 > 0:00:17They're instantly recognisable,

0:00:17 > 0:00:19with their elegant long tail.

0:00:19 > 0:00:21Artful assassins with

0:00:21 > 0:00:22a lightning-quick whip.

0:00:24 > 0:00:27Reaching up to 6m in length, they come armed with

0:00:27 > 0:00:32a scythe-like tail that can be as long as their body,

0:00:32 > 0:00:35packed with powerful muscle that extends right to the tip.

0:00:35 > 0:00:39To an unsuspecting fish, it's a lethal weapon.

0:00:39 > 0:00:44But why would these secretive sharks need such a striking tail?

0:00:44 > 0:00:48The deep waters off the Philippines are the perfect place to find them.

0:00:51 > 0:00:54Timing now is absolutely everything.

0:00:54 > 0:00:57This is the only time when it's going to be up here at our level

0:00:57 > 0:00:59and we stand a chance of seeing them.

0:01:00 > 0:01:02We head for the edge of the deep water,

0:01:02 > 0:01:06a sea stack reef where thresher sharks have been spotted before.

0:01:08 > 0:01:13And it's not long before a strange shape emerges from the dark.

0:01:13 > 0:01:14Coming towards us!

0:01:21 > 0:01:23Oh, my! It's a thresher shark.

0:01:25 > 0:01:29This is one of the greatest things I've ever seen.

0:01:29 > 0:01:32They're instantly recognisable with their long, elegant tail.

0:01:32 > 0:01:37And it's this that enables them to be a predator of precision.

0:01:37 > 0:01:42Look at the size of that tail! That is just insane.

0:01:42 > 0:01:46They're the only sharks to use their tail as a primary hunting tool.

0:01:47 > 0:01:50But how does it help them pick off their prey?

0:01:53 > 0:01:56Thresher sharks feed on small, fast fish.

0:01:56 > 0:01:59But rather than chase them down, it corrals them

0:01:59 > 0:02:02the same way a cowboy would with his cattle.

0:02:02 > 0:02:03When small fish feel intimated,

0:02:03 > 0:02:08they instinctively come together in a tight group known as a bait ball,

0:02:08 > 0:02:12and that's where the thresher shark's long tail comes in.

0:02:12 > 0:02:16It whips it over its head in about a third of a second,

0:02:16 > 0:02:20lashing out at the bait ball at about 30mph.

0:02:20 > 0:02:22This makes physical contact with the fish,

0:02:22 > 0:02:26but also creates a pressure wave that stuns them,

0:02:26 > 0:02:28making them easy pickings for the thresher.

0:02:31 > 0:02:35And with its prey cornered, the thresher shark moves in...

0:02:36 > 0:02:38..unleashing its killer tail...

0:02:40 > 0:02:43..helping it to devour its stunned supper with ease.

0:02:45 > 0:02:46The thresher shark.

0:02:46 > 0:02:50With a tail as long as its body, it corrals its victims

0:02:50 > 0:02:54before whipping them with a lightning-fast strike.

0:02:54 > 0:02:57It is, without doubt, the most striking shark of all.