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A. Gentoo penguin

This delightful dropping was left by the third largest species of penguin. Gentoo guano often comes in streaks because penguins create high pressures in their gut that shoot it a long distance. Researchers at Kochi University in Japan calculated that can reach 28 kilopascals – which is enough to propel their guano to a distance of 134 centimetres. That is like a human shooting their poo more than 3 metres.

In 2019, Bo Elberling at the University of Copenhagen in Denmark and his colleagues were studying penguin guano when they noticed they were beginning to get high. It turns out that , otherwise known as laughing gas. That’s because penguin diets contain a lot of krill and fish, both of which are rich in nitrogen.

B. Bald eagle

If you got this one right, it might have been because of the white colour many of us associate with bird poo. But bird poo is more complicated than many of us realise. Unlike most animals, which, crudely put, urinate and defecate through different holes, birds egest everything through one exit, the cloaca. They also convert their urine into concentrated uric acid to save water – this is the white, sticky stuff that gets onto cars. It is really closer to bird urine than faeces. For eagles, as for other birds, the solid waste is a separate thing, as seen in the photo. By the way, did you know that eagle excrement is often responsible for short-circuiting power lines? The birds use the towers that support power lines as lookout posts, and streaks of poo can provide a link between the power-carrying cables and the tower.

C. Mullein moth caterpillars

These little pellets are the waste of caterpillars, known to the people who study such things as frass. The specific animal that did this business is the caterpillar of the mullein moth, which lives throughout much of Europe. It is useful to scientists, who count the frass and use it as a proxy for how much food will be available to birds each spring. It is an important matter to monitor, since climate change is throwing off the timing of peak caterpillar hatching and chick fledging, which need to be in synchrony for the chicks to thrive.

The waste of other caterpillars is also useful. For instance, one study from 2017 found that the Mediterranean flour moth’s frass . It could be that caterpillar excrement is where we will discover some of our next best antibiotics.

D. Brown long-eared bat

Even for the trained naturalist, it can sometimes be tricky to tell the difference by eye between the guano of bats and droppings from rodents. That is easily solved if you pick up a pellet. Place it in the palm of your hand and drag it along with a finger. If it smears, it is likely to have been left by a mouse. If it crumbles to dust, then it is likely to be bat dung. All the UK’s bat species are insectivorous, so their poo is mostly made of the exoskeletons of moths and suchlike, giving it a dry consistency.

You can also tell which species of bat did the droppings by looking at their distribution. If they are smeared up walls, that often indicates pipistrelles. If they have built up in large piles, that indicates you have the brown long-eared bat close by. Oh, and if you do ever pick up animal faeces, be sure to wash your hands thoroughly afterwards.

E. Wild boar

In 2014, enterprising researchers calculated the average daily defecation rate for wild boar. It came out as between 3.8 and 4.3 poos per day, which is a lot when multiplied by many animals. Wild boar faeces can contain some nasty pathogens, including an assortment of parasitic worms that can infect humans. With the population of wild boar booming, notably in the US, that brings danger. You might think you are safe as long as you don’t touch the droppings. But in 2021, at the US Geological Survey and her colleagues analysed water from Congaree National Park in South Carolina, where people often do watersports. They looked for biological markers of excrement from humans, chickens, cows and swine – and found that . It is one reason why feral pigs are so problematic, along with the crops they destroy and traffic accidents they cause.

F. Snow leopard

Snow leopards are shy animals that inhabit the world’s highest, most inhospitable terrain. These features make them famously hard to study. But they mark their territory with scent, often before evacuating their bowels – and their scat is easier to find than the cats themselves. In 2017, Madhu Chetri at the National Trust for Nature Conservation in Nepal retrieved more than 300 samples of this cat scat from the central Himalayas. Their analysis revealed that the samples had been left by 34 snow leopards. This showed the animals’ population density was about – lower than previous estimates, which had probably counted the same animals twice.