Bright colours and shrill calls are all well and good, but if you really want to make a statement in the wild, it’s good to smell bad
Our sense of smell is one of the most reliable methods we have of gaining information about the world around us. If you don’t believe us, hold up a slice of meat that’s past its use by date and tell us what gives your brain the first clue that it isn’t safe for consumption. You’ll almost definitely pick up the rank smell before noticing any discolouration. Your eyes might deceive you and you might start hearing things, but your nose always knows.
Smells are generated when a creature or object releases volatile chemicals that evaporate and reach our noses in the form of a gas. Many animals rely heavily on this sense, because it’s an extremely effective early warning system in a world where many predators are camouflaged and move silently in an attempt to avoid detection. Smell is as intimate as you can get with another creature without directly touching it, by which point, for the hunted, things would already be too late.
The sense of smell is also linked to memory and emotion, and so many animals see the benefits in kicking up a stink. A timely unpleasant odour is often enough to put predators off, while other animals use smell to mark their territory, attract mates or communicate. Which animals, exactly, smell the worst is a matter of opinion – one beast’s stink is another beast’s perfume. But we’ve compiled a list of animals that are definitely in the running. Hold your nose, we’re going in…
It’s not just skunks; a wide range of animals, from millipedes to kingsnakes, defend themselves by spewing out a vile-smelling substance.
1. Skunks – The best defence is a good offensive smell
Protection-wise, skunks don’t have an awful lot going for them; they’re slow-moving, and don’t have particularly good eyesight or hearing. It’s unlikely they’d survive long were it not for their famously pungent defence mechanism. When threatened, the skunk sprays its attacker with a noxious chemical compound from nipples either side of its anus. The rubbery smell can linger for weeks. Worse still for the unlikely recipient, the concoction chokes the lungs and causes temporary blindness by irritating the eyes. The skunk can target a predator’s face at distances of up to three metres (10 feet).
2. Opossum – this North American marsupial has a nose for acting
We’ve all heard of the phrase ‘playing possum’, right? It comes from the opossum’s bizarre yet effective, tactic of ‘playing dead’ when it’s cornered by a predator.
This is actually an involuntary response – the opossum goes into shock and slips into a comatose state that can last for hours. Nonetheless, the performance – of drooling mouths and balled-up feet – is convincing enough to fool predators, and the deception even extends to the nose. Upon falling limp, the opossum excretes a green mucus that mimics the stench of decay. It all adds to the illusion of a meal that is well past its best before date, convincing the assailant to move on.
3. ‘Fulmar’ is Old Norse for ‘foul gull’, and here’s why
If you lived on a diet that exclusively consisted of seafood and garbage, your breath wouldn’t exactly be minty-fresh, either. But the ocean-faring fulmar, a relative of the albatross family, uses its death-breath to its advantage, projectile-vomiting a disgusting stomach oil mix that reeks of rotten fish at anything it considers a threat. This is a deeply unpleasant experience for, say, a rock climber that happens upon a fulmar nest. But for other seabirds, it’s often fatal, as the oils cause their feathers to lose their insulating properties. This means that when they land on water, instead of floating they sink to their doom.
4. African elephant – If you bump into a male in musth, urine trouble!
It isn’t all about self-defence; some animals kick up a stink as a warning to others not to encroach on their territory. For a few weeks every year, elephant bulls enter a period known as ‘musth’. During musth, the elephant’s testosterone levels are 60 times over normal levels, and even the most placid individuals become wildly aggressive and unpredictable.
Researchers believe this condition isn’t related to mating; rather, it’s a period where the male elephants establish pecking orders. To do this, they dribble their strong-smelling urine down their hind legs, and accent the scent with an oily mucus secreted from glands on their cheeks. The resulting toxic cocktail can be smelled over half a mile away.
5. Ring tailed lemurs – competing males hold ‘pong-offs’
Like many mammals, these small primates from the island of Madagascar use scent to communicate with each other and mark their foraging territory. They’re even equipped with a horny spur on each wrist, where their scent gland is, which they use to pierce tree bark before they rub their smell in.
Lemurs live in large social groups of about 20 to 30 individuals so during mating season there is a lot of competition amongst the males for the attention of the females. The male lemurs resort to chemical warfare, smothering their scent into their long tails and then flicking their appendage in their competition’s direction. These stands-offs can last for up to an hour before one of the lemurs is forced to back down.
6. Sloths smell of compost
Sloths are nature’s couch potatoes, and they have the hygiene routine to match. Sleeping for up to 20 hours a day, sloths move so little that an entire ecosystem of creepy-crawlies has seen fit to set-up home in their long, coarse fur. A single sloth can be home to thousands of beetles, hundreds of moths and, grossest of all, a thick coating of algae and mold that gives the sloth’s fur a green tinge. While the animal itself has no natural scent, its stowaways give the sloth a thick smell of vegetation, so perhaps it’s for the best that they spend almost their entire lives high in the treetops.
But believe it or not, having a coat of algae, although whiffy, is actually useful, and scientists believe that the sloth’s skin and hair has evolved to create conditions that encourage its growth. So while the algae gets a sheltered, damp home, the sloth gets a nifty set of camouflage from predators, and its skin can also absorb extra nutrients from its lodger. This kind of mutually beneficial partnership is called a ‘symbiotic relationship’.
7. The hoopoe stinks like rotten meat
Beautiful, isn’t it? But admire from a distance; the hoopoe reeks of rotten meat. It does so by choice, spreading a foul liquid secreted by its preen gland all over its feathers to deter predators and attract insects. Bacteria in the goop also combats feather-eating microbes.The female hoopoe then spreads this same liquid over its eggs to make them less palatable to hungry intruders. Tiny pits in the eggshell allow the smell to stick, making this a nest that could rival any teenage boy’s in the odour stakes.
8. Hyena-butter used to communicate through smell
Like the wolverine, hyenas use their scent to mark their territory, except in their case they do so by rubbing a sticky, stinky paste called ‘hyena butter’ on grass stalks, rocks and even each other. Hyena butter also serves another purpose for this highly-social animal – communication. Grass stalks coated in the stuff act as a notice board of sorts, allowing an individual to draw information about other hyenas nearby; young or old, pregnant or lactating. Each clan has its own distinctive scent, which researchers believe is generated by bacteria that lives in the hyena’s anal glands.
9. Introducing the hoatzin, or ‘stinkbird’
This rather clumsy bird inhabits the Amazon rainforest and appears to have more in common with the dinosaurs than other avians – hoatzin chicks even have claws on their wings, leading to comparisons to various ancient ‘missing link’ species such as the archaeopteryx.
It begs the question how such an ungainly species such as the hoatzin could survive into the present day. Well, one thing that likely puts predators off is that it stinks of fresh cow manure – which actually makes sense, because the hoatzin, which feeds almost exclusively on leaves, has evolved a digestive system similar to that found in cattle. Its crop serves as a fermentation chamber, where bacteria slowly (very slowly) breaks down the leaves until the bird can digest them. Because of its diet, the hoatzin spends much of its time lazing about – but then, there’s no rush. It’s not like the Amazon’s carnivores are queuing up for a sniff.
10. You won’t want to make yourself at home on the wolverine’s patch
Named the ‘skunk bear’ by the Blackfoot Indians that roamed the north-western United States, this hulking member of the weasel family is highly territorial, and uses scent to draw the boundaries of its breeding and feeding range. Until recently, it was thought that the wolverine marked its territory with its oily musk, but we now know that it does so by scent-marking with its urine as it goes about its daily animal business. It’s unmistakably strong, even by urine standards, because of the pine needles that form part of the wolverine’s diet.
But the wolverine has a final stinky trick up its unwashed sleeve. During lean times, this scavenger will store food in caches for later. They keep their bounty in cold, snow-covered crevices to keep bacteria at bay, and spray it with their aforementioned musk to put off anything else who might happen upon their larder.
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