The sexual success of the male spotted bowerbird depends on his gardening skills. In his patch of forest, where he displays to mates, he cultivates a small fruiting shrub called the ‘bush tomato’, with purple flowers and green fruit.

It’s not clear if his actions are deliberate or inadvertent, but it is clear that he doesn’t eat the fruit. The plant is there to provide him with decorations, to make his boudoir that much more enticing to a female. Aside from humans, the spotted bowerbird is the only other animal that grows a plant for purposes other than food.

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Doesn’t look a day older than 602,000

It looked like we had the polar bear’s origin story nailed down. Genetic studies suggested that between 111 and 166 thousand years ago, a group of brown bears, possibly from Ireland, split off from their kin. In a blink of geological time, they adapted to the cold of the Arctic, and became the polar bears we know and worry about. Fossils supported this story: the oldest polar bear bone is between 110 and 130 thousand years old.

But according to Frank Hailer at the Biodiversity and Climate Research Centre in Frankfurt, this story is wrong in two important ways. First, the polar bear aren’t just a branch of the brown bear family tree. They’re a separate lineage in their own right. Second, they around four times older than anyone had thought, arising around 600 thousand years ago.

If this new vision is right, the bear’s journey to polar dominance wasn’t a speedy sprint, but a more leisurely stroll. As a species, polar bears have seen many ice ages. Rather than being a symbol of extraordinarily fast evolution, they’ve actually had plenty of time to adapt to life in the freezer.

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For some scientists, an academic career can feel like crawling into a tower of crap. For other scientists, an academic career actually involves crawling into a tower of crap.

Since 1928, thousands of chimney swifts have roosted at Fleming Hall, a university building in Kingston, Ontario. For decades, they fed on local insects, and excreted the remains down one of the building’s chimneys. Around 2 centimetres of droppings, or ‘guano’, built up every year until the chimney was finally capped in 1992. To this date, Fleming Hall contains a hardened guano tower, two metres tall and 64 years in the making, which preserves a layered record of the swifts’ meals.

Now, a team of scientists, led by Joseph Nocera, have used this archive of historical poo to explain why the swift populations have fallen by 90 per cent since their heyday.

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We interrupt your regularly scheduled news programming to bring you this wonderful piece of trivia about kangaroo genitals.

Regular readers will know of my love for Inside Nature’s Giants, the British documentary where anatomists cut up large animals to examine how their bodies work and evolved. It’s a truly incredible show, combining unbridled joy at the natural world, drama, and solid educational value.

So far, it has brought us the horrifying throat of a leatherback turtle, the mysterious bloodsweat of a hippo, and the exploding insides of a beached whale. But this week’s episode may have topped all of that with the triple vaginas of the female kangaroo. The diagram above (an annotated screengrab from the show) explains the complicated plumbing.

This set-up is shared by all marsupials – the group of mammals that raise their young in pouches. Koalas, wombats and Tasmanian devils all share the three-vagina structure. The side ones carry sperm to the two uteruses (and males marsupials often have two-pronged penises), while the middle vagina sends the joey down to the outside world.

Note that the ureters, which carry urine from the kidneys to the bladder, pass through the gaps between the three tubes. In placental mammals, like us, the ureters develop in a different way, and don’t go through the reproductive system. As we develop, the precursors to the reproductive tubes eventually fuse into a single vagina. In marsupials, this can’t happen.

The programme also suggested that this might explain why marsupial embryos are born at such a premature stage of development. A kangaroo’s joey is about the size of a jellybean when it leaves the vagina, and it must endure an arduous crawl into the pouch. It’s possible that with such a narrow tube to go down, it couldn’t get any bigger before its birth.

With its complicated reproductive set-up, a female kangaroo can be perpetually pregnant. While one joey is developing inside the pouch, another embryo is held in reserve in a uterus, waiting for its sibling to grow up and leave. Indeed, a mother kangaroo can nourish three separate youngsters at a time – an older joey that has left the pouch, a young one developing inside it, and an embryo still waiting to be born.

We normally think of nests as the creations of birds, but our ape cousins build nests too. Orangutans, gorillas, chimpanzees and bonobos all build tree beds, by weaving branches, twigs and leaves together into a bowl-shaped cradle. These nests may provide safety from predators, or help the apes to sleep warm.* But it seems that their main function is to provide a good night’s rest. Sleeping against a tree bough is hard on a large ape, and nests offer a more comfortable option.

Of all the apes, orangutans reputedly create the sturdiest and most elaborate nests. By studying the physical properties of these treetop bunks, Adam van Casteren from the University of Manchester has found that the apes are skilled engineers. As befits animals of their intelligence, they don’t just mash branches together. Instead, they seem to have an impressive amount of technical knowledge about their construction materials.

Orangutans build their nests between 11 and 20 metres up. Once they choose a good spot on a sturdy branch, they bend or break other branches in towards them, and weave them in place to create a basic foundation. On top of that, they add smaller branches to create a ‘mattress’. That’s the basic model, and some orangutans add deluxe features. They can create blankets, by covering themselves with large leafy branches, or pillows, by clumping such branches together. They can loosely braid branches above their heads to make a roof, or even create a secondary ‘bunk-nest’ over the main one.

Like all apes, orangutans construct new ones every day. This means that intrepid scientists have plenty of old discarded nests to study. Van Casteren, along with Julia Myatt from the Royal Veterinary College, found 14 such nests in the Sumatran rainforest. They hoisted themselves into the canopy, attached ropes to different parts of the nests, and lowered these to the ground where team members were waiting with force gauges. “Climbing up into the high canopy is breathtaking,” says van Casteren. “You enter an area of the forest that isn’t used to having humans hang around in it.”

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Van Casteren found that orangutans use thicker branches in the structural foundation of the nest, and thinner branches in the mattress. The structural ones are four times stronger and four times more rigid, and they make the nest sturdy. The mattress branches are thinner and more flexible for comfort.

The orangutans also break the two types of branches in different ways. If you bend a dense branch, it will only break halfway – this is known as a “greenstick fracture (see below). That’s what van Casteren found in the structural part of the nest. Once broken like this, it’s surprisingly hard to fully snap a branch in two, even for a powerful animal like an orangutan. The trick is to twist the branch. The fracture extends outwards until the two halves come apart, producing two pieces with long tapered ‘tails’.  Van Casteren filmed the apes using this technique, and the found plenty of the distinctive tailed branches in their mattresses.

There are plenty of questions about the nests left to answer. For example, orangutans don’t choose their trees randomly, and actually avoid the most common species. What’s special about the ones they pick, and does that factor into the properties of the nests? The apes also learn their craft from adults, so do immature orangutans build nests with less distinctive foundations and mattresses? Van Casteren also wants to look at the nests of other great apes, and of other architects such as beaver or birds, to see if he gets similar results.

But for now, his data already show that orangutans make sophisticated technical choices when they build their nests. He thinks that they account for the different properties of the materials in their environment, and use those properties to make bunks that are both safe and comfortable. While many studies of animal intelligence focus on the use of tools, he argues that nest-building is no less mentally demanding.

Roland Ennos, who was involved in the study, says, “I hope helps to show how the evolution of intelligence can be driven by the need to deal with the mechanical environment, rather than the prevailing orthodoxy that it’s only the social environment that’s important.”

* In writing this story, I stumbled across a wonderful study by Fiona Stewart from the University of Cambridge, who tested the value of chimpanzee nests, by sleeping in them. She spent several nights in Senegal either sleeping in newly made chimp beds or on the bare ground. She was warmer in the nests, and received fewer insect bites. She didn’t get any more sleep, but what she got was less disturbed. “Terrestrial animals, including hyenas, were more concerning during ground sleep, although snakes were always a concern,” she writes, in a wonderfully deadpan way. Van Casteren, however, never tried to sleep in the orangutan nests that he studied. They are higher than a chimp’s and he was “too worried about falling out mid-dream”.

Reference: Van Casteren, Sellers, Thorpe, Coward, Crompton, Myatt & Ennos. 2012. Nest-building orangutans demonstrate engineering know-how to produce safe, comfortable beds. PNAS http://dx.doi.org/10.1073/pnas.1200902109

Images courtesy of Adam van Casteren

More on orangutans

• Expedition records show severe orangutan decline
• Orangutans are masters of conserving energy
• Photo safari – Orangutans Part 1
• Orang-utans use leaves to lie about their size

Leptopilina boulardi by Alexander Wild

In a French meadow, a creature that specialises in corrupting the bodies of other animals is getting a taste of its own medicine.

Leptopilina boulardi is a wasp that lays its eggs in fly maggots. When the wasp grub hatches, it devours its host form the inside out, eventually bursting out of its dead husk. A maggot can only support a single grub, and if two eggs end up in the same host, the grubs will compete with one another until only one survives. As such, the wasps ensure that they implant each target with just one egg. And if they find a maggot that has already been parasitized by another L.boulardi, they usually stay away.

Usually, but not always.

L.boulardi is sometimes infected by a virus called LbFV, which stands for L.boulardi filamentous virus. And just as the wasp takes over the body of its maggot target, so the virus commandeers the body of the wasp. It changes her behaviour so that she no longer cares if a maggot is already occupied. She will implant her eggs, even if her target has an existing tenant. After infected wasps are finished, a poor maggot might have up to eleven eggs inside it.

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It’s Easter. For some of people, this means they can take up all the vices they gave up for Lent, and binge on chocolate till they feel sick. For the hyenas of northern Ethiopia, it means it’s time to stop hunting donkeys.

Spotted hyenas are unfussy eaters and incredible opportunists. They can feast on rotting meat, anthrax-infected corpses, garbage and dung. They digest their food so completely that their droppings tend to consist of hair, hooves, and white powder made from broken-down bones. Unsurprisingly, they do rather well near urban environments, where humans provide them with a bonanza of scraps, leftovers, and livestock. The hyenas of northern Ethiopia get almost all of their food by scavenging on such sources.

Local humans tolerate the hyenas, which are affectionately known as “municipal workers”. The animals clean the waste from butchers, households, and even the local veterinary college. They’re seen and heard almost every night, and they almost never attack humans. Instead, they have come to depend on the Ethiopians for their food.

But that changes in the run-up to Easter. For 55 days, the local Orthodox Christians go through a period of fasting. Meat goes off the menu, and few animals are slaughtered. This lack of demand creates supply problems for the hyenas. Gidey Yirga from Mekelle University in Ethiopia has found that they sate their hunger by hunting instead.

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Here’s the fourth piece from my new BBC column

“What’s that Flipper? The treasure is over there?” So went a typical plotline for the popular TV series featuring the cute, bottlenosed dolphin who could communicate with his human guardians, and who – in the time-honoured fashion – used his animal powers to apprehend criminals.

The idea that animals like Flipper can communicate with humans is not just the preserve of the small and big screen. History is littered with celebrity animals who have communicated with human scientists, with varying degrees of success. Many apes, including Washoe and Nim the chimps, and Kanzi the bonobo, have learned to communicate by using sign language or symbols on a keyboard. Alex, an African grey parrot learned over 100 English words, which he could use and combine appropriately; his poignant last words to Irene Pepperberg, his scientist handler, were “You be good. I love you. See you tomorrow.”

Dolphins hold a particular fascination; we are captivated by their intelligence and beauty, and swimming with dolphins features regularly on lists of things to do before you die. Denise Herzing has a lifetime of such experiences. For the last 27 years, she has been swimming with a group of Atlantic spotted dolphins in Florida as part of the Wild Dolphin Project. She can identify every individual and they, in turn, seem to trust and recognise her. It is a solid foundation for the boldest attempt yet to talk with dolphins.

One-way chat

“Talk” is tricky to define. A SeaWorld trainer who prompts a dolphin to jump for fish is arguably communicating with it. But such simple one-way interactions are a far cry from the conversational world of Dr Doolittle. Here, the dolphin responds, but says nothing intelligible back. Herzing’s vision is much more ambitious – she wants to establish two-way communication with her dolphins, with both species exchanging and understanding information.

The idea of talking to dolphins has a long and chequered history. It was widely publicised in the 1960s by John Lilly, who argued that dolphins have such large brains that they must be extremely intelligent and have a natural language. All we had to do was to “crack the code”. Much of Lilly’s work was highly questionable. He once flooded a house to keep a captive dolphin, instigated failed attempts to teach them spoken English, and even gave the animals LSD (while taking the drug himself). But there is no denying his influence in popularising the idea of two-way dolphin communication. “He said that in a few years, we will have established complex dialogue with them,” says Justin Gregg from the Dolphin Communication Project. “And he was saying that every few years.”

Lilly was right about dolphin intelligence, but not dolphin language. A true language involves small elements that combine into larger chains, to convey complex, and sometimes abstract, information. And there is no good evidence that dolphins have that, despite their rich repertoire of whistles and clicks.

Little less conversation

Wild dolphin communication is hard to study. They are fast-moving and hard to follow. They travel in groups, making it hard to assign any call to a specific individual. And they communicate at frequencies beyond what humans can hear. Despite these challenges, there is some evidence that dolphins use sounds to represent concepts. Each individual has its own “signature whistle” which might act like a name. Developed in the first year of life, dolphins use these whistles as badges of identity, and may modulate them to reflect motivation and mood. This year, a study showed that when wild dolphins meet, one member of each group exchanges signature whistles.

But beyond this, dolphin chat is still largely mysterious. “To communicate with dolphins, we need to understand how they communicate with each other in the natural world,” says psychologist Stan Kuczaj at the University of Southern Mississippi. “We still don’t know basic things like what the units of dolphin communication are. Is a whistle the equivalent of a “word” or a “short sentence”? We don’t know.”

We may not be able to understand them yet, but we know that dolphins can learn to understand us. In the 1970s, Louis Herman taught an invented sign language, complete with basic syntax, to a bottlenose dolphin called Akeakamai. For example, if he made the gestures for “person surfboard fetch”, Akeakamai would bring the board to him, while “surfboard person fetch” would prompt her to carry the person to the board. His experiments showed that dolphins could understand hundreds of words, and how those words could be combined using grammatical rules.

What’s my motivation?

Herman’s work was groundbreaking, but this was still one-way communication. It focused on comprehension, not conversation. In the 1980s, Diana Reiss had more luck by showing that dolphins could use underwater keyboards to make basic requests. When they prodded keys with their snouts, a whistle would play and Reiss gave a reward like a ball. Eventually, the dolphins used the artificial whistles to ask for the associated rewards.

But as conversations go, these were shallow ones. “The dolphins were only really interested in communicating about needs that they had, like a tool they needed or a fish they wanted,” says Kuczaj, who was involved in a similar project at DisneyWorld’s EPCOT Center. “We hoped they would also comment on other things going on in the aquarium but they didn’t.”

It is difficult persuading dolphins to learn some arbitrary signals, like a whistle signifying a ball, and then use them in a social context, admits Gregg. “They don’t seem to run with it the same way that chimps or bonobos have. The big stumbling block is motivation. Dolphins don’t seem to care.”

Herzing disagrees. She notes that captive animals, which often lack stimulation, will respond to systems like the underwater keyboards. She thinks that these experiments disappointed because they were cumbersome. “The dolphins swim very fast and went to where they were requested, but humans are very slow in the water. There wasn’t enough real-time interaction.”

Chat line

Herzing is trying to solve that problem with Cetacean Hearing and Telemetry (CHAT) – a lighter, portable version of the underwater keyboards. It consists of a small phone-sized computer, strapped to a diver’s chest and connected to two underwater recorders, or hydrophones. The computer will detect and differentiate dolphin sounds, including the ultrasonic ones we cannot hear, and use flashing lights to tell the diver which animal made the call.

The CHAT device can also play artificial calls, allowing Herzing to coin dolphin-esque “words” for things that are relevant to them, like “seaweed” or “wave-surfing”. She hopes the dolphins will mimic the artificial whistles, and use them voluntarily. By working with wild animals, and focusing on objects in their natural environment, rather than balls or hoops, Herzing hopes to pique their interest.

Herzing emphasises that her device is not a translator. It will not act as a dolphin-human Rosetta stone. Instead, she wants both species create a joint form of communication that they are both invested in. She hopes that CHAT will tap into the “natural propensity” that dolphins have “for creating common information when they have to interact”. For example, in Costa Rica, distantly related bottlenose and Guyana dolphins will adopt a shared collection of sounds when they come together, using sounds that they don’t use when apart.

As with past projects, all of this depends on whether the dolphins play along. Kuczaj says, “It’s a remarkable challenge because she is working with wild dolphins so they’ve got the option to participate or not.” Here, Herzing has an edge, since the animals know her, and vice versa. “We’ve been observing them underwater every summer since 1985,” she says. “I know the individuals personally – their personalities and relationships. We’ve got a pretty good handle on what they’d be interested in.” Perhaps this combination of cutting-edge technology and old-school fieldwork will finally produce the conversations that have eluded scientists for so long.

In Australia, an ancient murder mystery is coming to a riveting conclusion, thanks to an unusual clue – not a fingerprint, or a bloody weapon, but fungal spores preserved in fossilised dung. The spores belong to Sporormiella, a fungus that only grows in mammal and bird droppings. Large plant-eaters provide it with vast banquets. In turn, the fungus reveals how many big vegetarians were living in the neighbourhood.

Scientists have used these spores to study the deaths of the giant animals that once grazed North America – “megafauna” such as mammoths, woolly rhinos, and more. Now, it’s Australia’s turn. By using Sporormiella records, along with other buried clues, Susan Rule from the Australian National University has found strong evidence that acquits a changing climate in the death of Australia’s giants. Instead, her study points the finger squarely at humans.

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Even the topmost layer of the ocean, just millimetres below the air above, is full of life. This zone, where two worlds meet, is home to small creatures like animal larvae, algae, bacteria, and other plankton. Among the most abundant residents of this zone are copepods – tiny relatives of crabs and shrimp. And some of them have the ability to leave this world altogether, and take to the air.

When threatened by fish, some copepods can jump straight out of the water and shoot over many times their own body lengths. From the fish’s point of view, its prey suddenly disappears.  Flying fish use the same tactic to escape from predators. Now, we know that one of the most common groups of ocean animals shares their strategy.

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