Category
🐳
AnimalsTranscript
00:00 Every year from November to April, blooms of jellyfish lay siege to Australia's northern coastline.
00:08 While some are harmless, others are amongst the deadliest creatures known to man.
00:19 The venom of the tiny Irukandji jellyfish is a hundred times more potent than a cobra's,
00:28 and a thousand times deadlier than that of a tarantula.
00:33 But Irukandji aren't considered to be the most dangerous marine stingers in these waters.
00:44 That title belongs to the box jellyfish, one of Australia's most notorious killers.
00:55 Over the last 130 years, these aquatic assassins have claimed the lives of more than 70 people.
01:03 The rapid onset of box jellyfish envenomation can lead to cardiovascular collapse and death in a matter of minutes.
01:14 It's a terrifyingly efficient way to subdue prey, which is typically small fish.
01:24 Stinging cells contained within the 10-foot-long tentacles inject venom upon contact, bringing about a quick death.
01:34 The extreme nature of the jellyfish's chemical weapon helps to protect its delicate tentacles from being damaged by a struggling victim.
01:44 Although not as ferocious as the great white shark, these toxic terrors have few natural predators.
01:54 Shunning the limelight, a reef stonefish conceals itself on the sea floor.
02:01 A master of disguise, it's easy to see how this predator got its name.
02:08 Its mottled colours blend in with the reef setting.
02:18 It will even tolerate algae growing on its skin to further aid concealment.
02:24 The stonefish is an awkward swimmer.
02:31 But it's patient, a required trait for an ambush predator.
02:44 By burying itself in the sandy seabed, it becomes almost invisible.
02:50 Even its large bulbous eyes are indistinguishable from its surroundings.
03:04 This nocturnal predator preys on crustaceans, small fish and cephalopods that stray too close.
03:15 The slightest movement would betray its presence.
03:25 Surprise is everything.
03:32 The stonefish's strike is explosive.
03:36 Its wide gape rapidly envelops unwary prey, which is swallowed whole.
03:52 Its use of surprise attack makes it a formidable predator.
04:01 But the stonefish is most renowned for its deadly defence.
04:08 It's the most venomous fish in the world.
04:13 Concealed within its dorsal fin are 13 needle-like spines.
04:21 Fed by venom glands, these spines form a lethal defensive array.
04:29 A toxin unique to stonefish, known as Verruca toxin, attacks the nervous and circulatory systems,
04:36 and can prove fatal to would-be predators.
04:40 In humans, stonefish envenomation can result in severe pain
04:46 and life-threatening restrictions to blood flow and breathing.
04:51 Hunters, beware.
04:54 More often than not, these silent assassins will have the last laugh.
05:01 Roughly the size of a baseball, the soft-bodied blue-lined octopus looks deceptively vulnerable.
05:13 And with a relatively short lifespan of just seven months,
05:19 the species depends upon some rather extreme survival strategies.
05:24 This sea snake is prowling for food.
05:32 The octopus has a choice to make.
05:37 Hide or stand and fight?
05:40 It opts to hide.
05:45 Like most cephalopods, the blue-lined octopus is a master of disguise.
05:51 Sophisticated skin tissues allow it to rapidly change not only its colors,
05:57 but also the texture of its skin to better blend in with its surroundings.
06:03 The sea snake continues its search for a meal.
06:11 [Music]
06:16 But some predators are armed with more refined senses.
06:21 The hammerhead shark possesses an array of electroreceptors
06:34 that can detect even the best hidden of prey on the seafloor.
06:40 Confronted with the threat, the blue-lined octopus decides to change tactics.
06:46 It sends a vivid message.
06:50 Iridescent blue markings pulsate across its body,
06:54 warning the predator that it's armed and dangerous.
07:06 Its deadly bite is 10,000 times more toxic than cyanide.
07:12 In humans, envenomation can cause respiratory failure,
07:17 leading to cardiac arrest and eventually death in as little as a few minutes.
07:24 In nature, such threat displays are generally heeded,
07:29 and the hammerhead continues on its way.
07:34 [Music]
07:37 On a smaller scale, the blue-lined octopus is also a predator.
07:42 It scours the ocean floor, searching for small fish and crustaceans.
07:48 As a soft-bodied cephalopod, it's vulnerable to counterattack,
07:53 and this crab's pincers could inflict grievous bodily harm,
07:58 albeit in self-defense.
08:01 [Music]
08:06 A surprise attack presents the best chance of success.
08:11 [Music]
08:24 The octopus's dexterous tentacles restrain the crab's menacing claws,
08:30 while its sharp beak easily penetrates the crab's exoskeleton,
08:35 delivering its toxic bite.
08:38 The crab quickly succumbs to a lethal combination of toxins
08:45 contained within the octopus's venom.
08:48 There's no doubt with this pint-sized perpetrator,
08:52 blue means back off.
08:56 [Music]
09:02 [Music]