Snakes have been around for a long time: body fossils found in the UK, Portugal and the US stretch all the way back to the late Jurassic period, about 150 million years ago. Representative Image.
| Photo Credit: K.R. Deepak/The Hindu

Snakes are familiar, distinctive – and often feared – reptiles. And they’ve been around for a long time: body fossils found in the UK, Portugal and the US stretch all the way back to the late Jurassic period, about 150 million years ago.

Until now, though, there hasn’t been a single description of a surface fossilised snake trace – a mark on a surface that’s become cemented and re-exposed over time – anywhere in the world.

There are probably several reasons for this. One is that the tracks of large quadrupeds (four-legged animals), including dinosaurs, are easier to recognise than those of snakes. Another reason could be that snakes tend to avoid sandy or muddy areas in which their trails could be registered, preferring vegetated terrain. Maybe, as the weight of the snake is distributed over its entire length, the trails are shallow and are not easy to identify.

Or perhaps researchers are not adequately familiar with the types of traces that snakes can create.

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We are part of an ichnological team – experts in identifying fossil tracks and traces. In a recently published article in the journal Ichnos, we described the first snake trace in the fossil record, which we found on South Africa’s Cape south coast. It dates to the Pleistocene epoch, and our studies have shown that it was probably made between 93,000 and 83,000 years ago, almost certainly by a puff adder (Bitis arietans).

As this is a world first, our research team was obliged to create a new ichnogenus and ichnospecies, Anguinichnus linearis, to describe the distinctive pattern in the sand registered by the puff adder.

A snake and a buffalo

The puff adder is a not uncommon sight on the Cape south coast today and, with good reason, strikes fear into residents and visitors: its cytotoxic (tissue-destroying) venom can cause the loss of a limb or worse. It habitually suns itself on trails, staying motionless, and then strikes without warning.

We found the trace fossil in the Walker Bay Nature Reserve (adjacent to Grootbos Private Nature Reserve), just over 100 kilometres south-east of Cape Town.

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Intriguingly, a long-horned buffalo – an extinct species – had walked across the same dune surface soon after the snake left its trace. We know this because one of the buffalo’s tracks is superimposed on the puff adder trace, slightly deforming it.

The puff adder and long-horned buffalo traces were found on the surface of a loose slab, 3 metres long and 2.6 metres wide, which had become dislodged and fallen down onto the beach from overlying cliffs. The slab is submerged twice a day by high tides. We were fortunate to discover it when its surface was bare, as repeat visits have shown that it is often covered in algae or by a thick layer of beach sand.

Snakes in motion

Snakes use four main types of locomotion. Each results in distinctive, recognisable traces.

Puff adders are heavy, thick-set snakes with an average adult length of less than a metre. They mostly employ rectilinear motion, leaving a linear, sometimes slightly undulating trace, often with a central drag mark registered by the tail tip. In this form of motion the snake uses its weight and its belly muscles and grips rough areas on the surface with the posterior edges of its scales. It is drawn forwards through the muscular contractions, creating a linear trace.

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We also found possible trace evidence at other sites on the Cape south coast of sidewinding and undulatory motion, but this was inconclusive. We will be looking for further, more conclusive evidence.

Filling important gaps

The newly described puff adder traces help fill a gap in the Pleistocene trace fossil record from the region. More than 350 vertebrate tracksites have been identified, of mammals, birds and reptiles. Most of these sites were registered on dune surfaces, which have now become cemented into aeolianites and re-exposed. Our latest find is yet another global first for the Cape south coast.

With other vertebrate groups, such as dinosaurs and crocodiles, the trace fossil record has substantially augmented the body fossil record, providing new insights. Hopefully this discovery will act as a spur to identify other snake traces from around the world from older deposits, and thus increase our understanding of the evolution of snakes and help to fill a substantial gap in the global trace fossil record.

Many people love eye an echidna. Their shuffling proceed, inquisitive gaze and protecting spines are detectable, coupled with the coarse hair and stubby beak.

They seem like a unusual mix of hedgehog and anteater. However they’re no longer similar to those creatures in any respect. They’re much more secret and peculiar than recurrently assumed.

Australia has only one species, the short-beaked echidna (Tachyglossus aculeatus), which roams just about all the continent. Nevertheless it has 5 subspecies, which might be regularly markedly other. Tasmanian echidnas are a lot hairier and Kangaroo Island echidnas tied lengthy mating trains.

Listed below are 4 issues that produce echidnas notable.

1: They’re historical egg-laying mammals

Decrease-beaked echidnas are one in every of simply 5 species of monotreme surviving on this planet, along the platypus and 3 worm-eating long-beaked echidna species discovered at the island of Unused Guinea.

Our habitual short-beaked echidnas can weigh as much as six kilograms – however the Western long-beaked echidna can get a lot greater at as much as 16kg.

Those historical mammals lay eggs via their cloacas (monotreme way one opening) and incubate them in a pouch-like pores and skin wrinkle, nurturing their slight, jellybean-sized younger then hatching.

Scientists believe echidnas started as platypuses who left the H2O and advanced spines. That’s as a result of platypus fossils advance again about 60 million years and echidnas just a quarter of that.

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Remarkably, the echidna nonetheless has rudimentary electroreception. It is smart the platypus depends upon its skill to sense electrical boxes when it’s looking on the base of dim rivers, given electrical boxes unfold extra simply via H2O. However on land? It’s most likely echidnas worth this skill to sense ants and termites shifting via wet park.

It probably got its English title in homage to the Greek mythological determine Echidna, who was once half-woman, half-snake, and the mummy of Cerberus and Sphinx. This was once to indicate the animal’s mixture of half-reptilian, half-mammal characteristics. First Countries teams knew the echidna via many alternative names, corresponding to bigibila (Gamilaraay) and yinarlingi (Warlpiri).

2: From deserts to snow, echidnas are remarkably adaptable

There are few alternative creatures ready to survive circumstance levels as vast. You’ll to find echidnas on northern tropical savannah amid intense humidity, on coastal heaths and jungles, in arid deserts or even on snowy mountains.

The 5 subspecies of short-beaked echidna have distinct geographic areas. The only maximum people shall be habitual with is Tachyglossus aculeatus aculeatus, frequent throughout Queensland, Unused South Wales, South Australia and Victoria. You’ll call to mind this as “echidna classic”.

Next there’s Kangaroo Island’s T. aculeatus multiaculeatus, Tasmania’s T. aculeatus setosus, the Northern Length and Western Australia’s T. aculeatus acanthion and the tropical subspecies T. aculeatus lawesii present in Northern Queensland and Papua Unused Guinea.

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You could suppose subspecies wouldn’t be too other – another way they’d be other species, proper? In reality, subspecies can also be markedly other, with permutations to hairiness and the dimension and width of spines.

Kangaroo Island echidnas have longer, thinner, and paler spines – and extra of them, in comparison to the mainland species. Tasmanian echidnas are neatly tailored to the chilly, boasting a lushness of too much hair. Every so often you’ll be able to’t even see their spines amidst their hair.

2: From deserts to snow, echidnas are remarkably adaptable

Remarkably, the subspecies have very other approaches to mating. You’ll have perceivable movies of Kangaroo Island mating trains, a spectacle the place as much as 11 men fervently pursue a unmarried feminine all through the breeding season. Alternative subspecies do that, but it surely’s maximum habitual on Kangaroo Island. Scientists consider that is because of people density.

Being pregnant in most cases lasts about 3 weeks then mating for Kangaroo Island echidnas, adopted via a protracted lactation duration of 30 weeks for the infant puggle.

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However Tasmanian echidnas behave very otherwise. All through the iciness mating season, men search out hibernating women folk and wake them as much as mate. Intriguingly, women folk can put their being pregnant on accumulation and advance again into rest. They even have a shorter lactation duration, of best 21 weeks.

What concerning the echidna subspecies we’re maximum habitual with? T. aculeatus aculeatus has a in a similar way brief lactation duration (23 weeks), however infrequently engages in mating teach statuses. Nearest looking at the pregnancies of 20 of those echidnas, my colleagues and I came upon this subspecies takes simply 16–17 days to advance from mating to egg laying.

4: What do marsupials and monotremes have in habitual?

Marsupials endure reside younger after they’re very tiny and allow them to entire their construction in a pouch. Regardless of this key residue with monotremes, there’s an enchanting similarity between Australia’s two most renowned mammal households.

At 17 days then thought, the embryo of the tammar wallaby (Macropus eugenii) hits virtually precisely the similar developmental milestone as echidna embryos. Each are within the somite degree, the place paired blocks of tissue mode alongside the notochord, the transient precursor to the spinal twine, and every have round 20 somites.

What’s notable about this? Monotremes branched off from alternative mammals early on, between 160 and 217 million years in the past. Marsupials branched off after, at round 143–178 million years in the past.

But in spite of hundreds of thousands of years of evolutionary power and alter, those very other animals nonetheless collision a key embryo milestone on the similar past. This putting parallel suggests the intricate procedure has been conserved for over 184 million years.

In echidnas, this milestone is secured to egg-laying – the embryo is packaged up in a leathery egg the scale of a grape and laid into the mummy’s pouch. The infant puggle hatches 10–11 days after. In tammar wallabies, the embryo continues to assemble in-utero for every other 9–10 days prior to being born.

So the then past you notice the common-or-garden echidna, jerk a pace to understand what a notable creature it’s.

In this photo released by Xinhua News Agency, a sun bear interacts with tourists at the Hangzhou Zoo in Hangzhou in eastern China’s Zhejiang Province on Wednesday, Aug. 2, 2023. The zoo in eastern China is denying suggestions some of its bears might be people in costumes after photos of the animals standing like humans circulated online. The Hangzhou Zoo said on its social media account the sun bears from Malaysia are smaller than other bears and look different but are the real thing.
| Photo Credit: AP

When Angela, a Malayan sun bear, stood up and waved to visitors to her enclosure at the Huangzhou Zoo in China on July 27, she became a social media sensation. Her build, posture and seemingly friendly gesture seemed so human that people speculated that she was actually a costumed performer. The talk gathered so much momentum, the zoo had to deny the claims. But that just goes to show how little people know about these fascinating animals.

Angela is an authentic bear, well known for her antics at the zoo.

Grizzlies and polar bears are huge, standing 2.5 metres tall and weighing 400-700kg. But not all bear species are so big. Angela’s dainty 1.3m, 50kg stature is typical for a sun bear. Sun bears often stand upright and mothers will even walk around cradling their babies in their arms. The Paradise Wildlife Park in Hertfordshire, UK, recently posted a video of one of its sun bears, Kyra, standing upright.

Bears generally carry some extra fat and tropical sun bears don’t have the thick fur of their cold climate cousins. So poor Angela’s skin folds are there for all to see as she suffers some “pants sag”.

What about the waving?

Only animals that evolved climbing ability, like bears, raccoons, primates and some of the cat family, can turn their palms upwards and move their forearms side-to-side. This allows them to grab hold of trees. Animals that evolved to run long distances, like deer, wolves and horses, can’t do this.

Think about your pet dog giving its paw. The motion is quite different to a wave. Sun bears are the strongest climbers in the bear family, and so, in some sense, Angela is waving because she can.

As for her motivation, if she was frightened, she’d probably run away from the crowds and hide in her indoor space. Although sun bears do stand up and display their creamy orange chest patches when they feel threatened, she sees humans every day. We think that most probably she simply wants to stand up and clearly occupy her territory when faced with visitors, a bit like we might stand on our front step when strangers call on us.

Standing up also allows sun bears to smell over longer distances. Although solitary in the wild, sun bears are good communicators when housed in groups and are the only animals other than humans and gorillas that can mimic each other’s facial expressions for social appeasement. It is possible Angela was mimicking the visitors waving at her.

Nevertheless, we probably shouldn’t credit Angela with human-like motivations for waving. Sun bears use their paws a lot for finding food in the wild, such as fruits, ants, beetles, termites and even honey. Standing on their back legs frees up their front legs to rip, poke and prod until they’ve got their dinner. They also have a 30cm long tongue that helps them lick up their food. Most likely then, Angela was just making a gesture of displaced curiosity, like a cat pawing at an image on a TV screen, while defending her enclosure.

A teaching moment

Since Angela appeared on the Chinese blogging site Weibo, visitor numbers are up by 30% at the Huangzhou zoo and millions have taken an interest internationally. While this story is cute, there’s a serious side. Sun bears, properly known as Helarctos malayanus, are listed as “vulnerable” on the International Union for the Conservation of Nature’s (IUCN) red list of threatened species. This means sun bears urgently need protection.

Six out of the world’s eight bear species are threatened with extinction. South China is part of the natural range of sun bears but very few are left in the wild in China. The majority of the remaining wild sun bear population lives in Malaysia, Thailand, Laos, Cambodia, India, Bangladesh and Myanmar.

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Sun bears can live over 20 years but are slow to mature. Mothers invest a lot of care into raising their one or two cubs and don’t get pregnant again until their cubs become independent, at around three years old. It’s why males of most bear species often try to kill a female’s cub, to cause her to become receptive to mating. She won’t engage if she has cubs.

Like all Asian bear species, sun bears are poached for bile from their gallbladders, which are used in traditional medicine. They are also killed for their paws, which are eaten as an expensive delicacy. International trade in these bear parts is banned under the Convention on International Trade in Endangered Species (Cites) but enforcement is inadequate.

China is working to improve wildlife protection with stricter laws and by designating more national parks.

Zoos worldwide are also playing an important role in educating the public about conservation. For many years, China has focused its efforts on protecting the giant panda. Panda conservation is driven by the iconic status of pandas both in China and abroad. But thanks to Angela, another bear species is now sharing the attention.