They may be aquatic, but it can feel like we have a lot in common with dolphins. They are intelligent, friendly, and have been known to get together to rescue other dolphins and even humans. Many people put swimming with dolphins on their list of things to do before they die, others will pay top dollar for a session of so-called dolphin therapy. And thanks to their smarts, agility and sonar, dolphins even make excellent soldiers – in fact, much of what we now know about the animals began with the US military’s dolphin training programme in the 1960s.
As our list of top dolphin skills shows, they are astounding communicators, have decades-long memories and an entire suite of senses divergent from our own, although they can be overly ambitious when deciding what to have for lunch…
1. Sounds twistin’ my melon, man
Dolphins, and their cousins, the porpoises, use high-frequency sonar clicks to echolocate and home in on their prey. They can produce, focus and direct the sounds without even moving their heads. How they achieve such a degree of control stumped scientists for a long time. The key turned out to be a large, fatty organ in their foreheads called a melon. By changing the shape and density of the melon with their facial muscles, and working in conjunction with air sacs in the head and the skull bones themselves, dolphins and porpoises can direct, focus or widen their sonar beam. The returning sounds are picked up by a fat-filled cavity in the jaw and conducted to the inner ear before hitting the brain for processing. A marvel of evolution.
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2. Electromagnetic sensations
Dolphins are sensational creatures in more ways than one. They can even sense . To prove it, researchers put two barrels in a pool, one containing a magnetised neodymium block, the other a non-magnetic block of the same shape and density. The only difference in the barrels was the magnetisation, yet bottlenose dolphins made a beeline for magnetised one. So-called magnetoreception could be a useful for navigation in the murky depths, which are shot through with the planet’s magnetic field lines.
If sensing magnetic fields wasn’t enough, another species of dolphin has been shown to pick up electrical signals too. Guiana dolphins detect the electrical fields generated by their prey. “Electroreception is good for sensing prey over short distances, where echolocation isn’t so effective,” Wolf Hanke at the University of Rostock in Germany told us in 2011. The dolphin’s electrosensory organs evolved from the whisker apparatus of its mammal ancestors.
3. Hello Dave, long time no sea
The phrase “Elephants never forget” does a disservice to dolphins. Not only do dolphins appear to have a whistling system akin to naming, they They also remember other dolphins’ names – or “signature whistles” – even after decades spent apart. In a 2011 study that monitored 179 pairs of wild bottlenose dolphins on the Florida coast, the pairs that consisted of a mother and her calf, or two adults that normally moved and hunted together, exhibited an intriguing behaviour that had not previously been documented. When these pairs became separated, one would repeatedly call to the other with a signature whistle, which the other would mimic as a way of finding one another again.
And subsequent research on dolphins that were once separated and reunited decades later revealed that they effectively have lifelong memories of other dolphins. They , but not to those of dolphins they’d never met before.
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4. They won’t be caught napping
Humans are lucky if they can stay alert for 24 hours in a row. Thanks to a rare talent in just a few animals – the ability for the brain to sleep one hemisphere at time – dolphins can stay alert and active for many consecutive days and nights. To explore the extent of this “unihemispheric sleep”, Sam Ridgway had captive dolphins listen to a series of short beeps, one every 30 seconds. Every few hours a longer beep meant a food reward was available if the dolphin hit a lever. The dolphins could stay alert for as long as 120 hours in a row without any decline in performance. Sadly, Ridgway couldn’t measure how bored the dolphins were after five days of non-stop beeps.
And finally…
5. I love giant octopuses – but I couldn’t eat a whole one
Dolphins are famously smart, but that doesn’t mean they never bite off more than they can chew. Octopuses are a risky meal for dolphins, which can struggle to get the tentacled creatures down without incident. Last year, an Indo-Pacific bottlenose dolphin known to researchers as Gilligan washed up on a beach in Western Australia. Its octopus prey had suffocated the optimistic dolphin, and the attempted meal killed all involved. The pictures were reminiscent of a scene from the Alien movies.
Read more: Talking dolphins and the love story that wasn’t; Dolphins have a language that helps them solve problems together; Death in dolphins: do they understand they are mortal?
