Nature’s Weirdest Events (Series Four)

I reviewed the previous series of this last year, and at the time I had no idea that it was the third series. But here is is again, following the same format of three episodes documenting unusual events in the animal kingdom, and still presented by Chris Packham.

Some of the events were of animals in places you might not expect to find them. One was a beach that had swimming pigs. Not the actual Bay Of Pigs, which is in Cuba, or the Bay Of Pigswatch which was a sketch on Muppets Tonight featuring characters like Spamela Hamderson and David Hoggselhoff. This one was in the Bahamas. Some people were out there on a boat and dropped food scraps into the sea, the scent bringing pigs out from the woods. They jumped into the sea, and turned out to be very good at swimming. We usually imagine pigs wallowing in the mud in a sty on a farm, but there is possibly a connection with that and them being strong swimmers. Pigs don’t have sweat glands; that’s why they wallow in mud in the first place, it’s a way for them to keep cool. So from an evolutionary point of view, it makes sense for pigs to have developed to take to the water. It is not known how these pigs ended up in those woods, they were likely put there by humans, but they have thrived there.

In Bangkok a shopping mall caught fire and the building was left derelict. It no longer had a roof, so rain water collected in the mall, eventually flooding it. Now thousands of fish live there! It’s a similar situation to the pigs in the Bahamas. It is not known for sure how they got there, it is speculated they were introduced by humans as a way of reducing the number of mosquitoes, but however they got there, they have thrived. It has become a wildlife attraction, with people going there to feed them, and sometimes for fishing. The sight of seeing fish swimming underneath the ruins of an escalator and in flooded empty shops is one to behold.

Off the coast of Japan is Okunoshima Island, which is also known as Rabbit Island because of the hundreds of rabbits there. It has become a very popular tourist attraction, and the rabbits seem just as eager to see the tourists, mobbing and chasing after them. They like them because tourists feed them. This behavior is strange for rabbits, as most of the time they are easily scared and run away very fast. The difference with this island is that they have no natural predators and they associate humans with feeding time. That’s also why there are so many rabbits there. Most of the time in the wild rabbits have a short life expectancy because of the sheer number of predators they have. It’s for that reason they have evolved to breed so quickly and run so fast. But they have no predators here, and breed just as much. As seems to be pattern, how they got on the island in the first place is a mystery, one theory is that they may be descended from laboratory rabbits from when the island was used to make poison gas during the Second World War. The programme mentioned Tashirojima Island, also known as Cat Island, which at the risk of pointing out the obvious is similar to Rabbit Island, but with cats instead, in fact cats now outnumber humans there.

One of the funniest and most surreal sights in the series was of some goats standing on the branches of a tree. Goats in trees has become an internet meme, with some people thinking that Photoshop might have been involved. But as unusual as it looks, it makes sense, as goats are very good climbers, their cloven hooves allowing them to climb mountains with ease. Just as they will climb mountains to find grass high up, they will climb up a tree to eat the leaves on the branches.

While the above examples were about cute animals, other events in the series were more like something out of a horror or sci-fi movie, with the show adding Theremin on the soundtrack to invoke this idea with the viewers.

In China in 2008 while they were preparing to host the Olympics, some of their coasts became covered in seaweed, which at first glance looked like the sea had become slime. It was an algal bloom, but those don’t usually grow that much. Upon investigation, it turned out people had in fact contributed to this weird natural event. The alga had come from a nearby seaweed farm, seaweed being grown as part of manufacturing sushi. The alga was cut off and discarded, allowing it to float into conditions which made it grow. It was during the hot summer and that the seas had been pumped with farming waste, which meant there were a lot of nutrients for the alga to feed on. This massive algal bloom has apparently continued every year in China since.

Jellyfish also ‘bloom’, and once again while there’s unusual about that per se, the growth is becoming bigger and lasting longer, and its causing us problems as the jellyfish feed on plankton. As plankton are a basis for an ecosystem, less plankton is bad news for all the species higher up the food chain. But we’ve only got ourselves to blame. Overfishing has got rid of a lot of the jellyfish’s predators, and global warming means warmer seas, perfect conditions for the jellyfish blooms to increase.

Horseshoe crabs were compared on a clip in this programme to Alien Vs. Predator. They do look like they might have been the result of an unfortunate one night stand between the Alien Xenomorph and the Predator, as they resemble the Alien Facehuggers, and have armour very similar to the Predators. Indeed, the horseshoe crab was one of the inspirations for the Predator. They come on New York beaches to breed. But the most bizarre thing about this event was that humans milk them for their blood! Their blood clots around bacteria and toxins, so we use it to test medical equipment. The sight of the alien-looking creature in a labratory tank looked very science fiction. One contrast between horseshoe crab blood and human blood is that while human blood is red, horseshoe crab blood is blue. The reason for this is the difference in what each blood is made up of. Human blood is red because we have iron in our haemoglobin, while horseshoe crab blood is blue because they have copper in their haemoglobin.

You can see why when these events occur with no obvious explanation that people’s minds may go to the supernatural as a potential cause, or even to think it might be the result of an alien invasion. But the causes of these events tend to be terrestrial rather than extraterrestrial, and a fairly normal part of nature. An example in this programme is that it has been known for earthquakes to generate an electrical charge which manifests itself as flashes of blue or green light in the sky. Another was in a desert in eastern California some stones seemed to be moving by themselves overnight, leaving trails in the sand behind them. One of the explanations people thought up was aliens yet again, but the cause turned out to be ice of all things. Water underneath the rocks froze during the night, then the ice cracked in the sun the next day, meaning only a light breeze would be needed for the rocks to slide.

“Star jelly” is a concept which has gone back centuries. It is a clear goo, and as it was said to be found around the same time meteorites were sighted, people thought it may have come from a higher power or from outer space.  But it is actually from Earth. DNA tests on some found that it was the remains of  female frog that had been eaten by a magpie, the goo being the protective layer they use to keep their eggs in. Another thing that has been called “star jelly” in the past is slime mould, which also made an appearance on this programme. While it has no brain, it can grow to a massive size. It grows as it finds food, reaching out tubes which stop short if they can’t find food, but the tubes which do find food continue to grow (and grow, and grow).

Sightings of sea creatures in the past inspired stories of mythical creatures, as it would be difficult to see a creature from a distance and hidden in the water. The male narwharl whale’s tusk was mistaken for a unicorns and probably gave rise to the legend of unicorns being stuck in the sea after missing Noah’s Ark. Mermaids are generally thought to have been dugongs. This programme featured the oarfish, which can grown up to 36 feet long and probably inspired stories of sea serpents and it has even been suggested the oarfish might have been the Loch Ness Monster.

Snakes made a few appearances in this series. In one episode we saw a writhing mass of them in Canada during their mating season. As with a lot of animals, males compete to mate with females. But some male snakes have an unusual way of doing that. They will give off a female pheromone which causes other males to be attracted to him and rub against him. This will increase his body temperature, which is very important to snakes as they are ectothermic, which means that they have to get heat from outside sources. If the temperature of the environment is warm, they have a lot of energy, if its cold they have less energy. By essentially taking the heat off other males, this snake will have more energy to compete for females.

Those particular female snakes have no trouble finding a male to mate with, if anything they have a problem of too many males wanting their attention. But with other snakes, females have even found a way around the problem of not being able to find a male. The programme showed a female anaconda who has managed to give birth without mating with a male, essentially by cloning herself. She’s not unique either, it has been observed in a few other species. The process is called parthenogenesis, which roughly translates from Greek as “virgin birth”. Some species of whiptail lizard do this as a matter of course, and all are female. They still mate with each other though, to trigger ovulation.

The tarantula hawk wasp is so-called because it preys on tarantulas. We saw a clip of one fighting a tarantula, which did look a bit like an insect version of King Kong vs. Godzilla, but this wasn’t a “who’s the hardest”, it was about survival. The wasp stings the tarantula, paralysing it, then she drags it away, buries it alive, and lays an egg inside it. For the tarantula, it’s a slow, gruesome death. The egg hatches into a grub, and over a couple of weeks eats all of the tarantula from the inside, starting with drinking its blood  and ending with eating its heart and brain. You can see why parasitic wasps aren’t a very popular creature with us. As humans we can sometimes empathise or even admire predatory animals, indeed technically humans are predatory animals ourselves, but parasitic creatures which feed off a host and kill it in this way seem a bit disturbing and unsettling to us. But then, should we really judge other creatures behavior by human standards? The programme seemed aware that parasitic wasps have a bad public image, and did a bit of positive PR for them, describing the tarantula hawk wasp as a “caring” “clever” and “brave” mother.

In humans, and mammals in general, the male is usually bigger and physically stronger than the female, but with many insects its the other way round. This is because often the males only job is to mate, while the females job goes further as she has to find a tarantula as food and a place to lay her egg. So the tarantula hawk wasp mother always makes sure she lays her female eggs in the bigger tarantulas and her male eggs in the smaller tarantulas.

Many invertebrates have biology and reproduction which to us looks bizarre as it is very different to ours. Slugs for example are hermaphrodites, so are both male and female at the same time. Their mating involves them hanging off a thread of mucus, wrapping around each other, then their penises will come out from their heads and they will swap sperm and fertilize each others’ eggs. It is possible for them to self-fertilize, but given the choice they’d rather mate with another slug.

It is well known that some insects can spread disease, but there is one that can give people an allergy to red meat! That is the Lone Star tick. It is a bloodsucker which tends to feed off large mammals. If they feed off say, cattle or a deer and then feed off a human, they may end up putting a carbohydrate called alpha gall into the human’s bloodstream. The programme pointed out that alpha gall is in all non-primate mammals, and is harmless to humans most of the time, but if it enters the bloodstream via the tick, the body sees it as an intruder. That itself is easy to solve, as antibodies are sent to take care of it. The problem comes when the infected person later eats red meat. Their body now sees alpha gall as an intruder they have dealt with before, so it responds the same way by sending antibodies to get rid of it. There will be a lot more alpha gall than when the tick sent it in, which means more antibodies, and this is the allergic reaction. Fortunately for people affected with this, the allergy usually wares off over time.

Starfish (or “sea stars” as the programme called them) may qualify as “weird nature” just for how they are, because of their regenerative abilities. If they lose an arm they can just grow a new one, and sometimes they can even regenerate a new body from a single arm.  But there is an increase in them dying from a densovirus, which is particularly nasty as it causes them to either tear their own arms off or for the arm to crawl away from the body of its own accord.

In Miami an aquarium owner noticed the coral in one of his fish tanks seemed to be moving around or going missing. He at first thought it was his staff, but the culprit turned out to be inside the tank; a bobbit worm. It’s certainly a very unusual looking creature, looking more like a snake with spikes all over its body, and it has a rainbow glow on a patch of its skin. They hide in the sand and pounce on fish as they go by. They can stay very well hidden and most of the time aren’t noticed in fish tanks.

Birds evolved from dinosaurs, and there are still some birds around today where the link seems clear, like the ostrich, the emu or the shoebill. But even they don’t look as dinosaur-like as the cassowary in Australia. It has a blue and red face, long scaly legs and a horn-like crown on its head. A clip on the programme showed a view of it from a car, and the grainy, blurry footage made it look like something straight out of Jurassic Park. Despite their appearance, cassowarys are not normally aggressive, and they tend to eat fruit.

Prairie dogs have a very sophisticated language, apparently more sophisticated than whales and dolphins. Tests have shown them to be able to come up with a different call for different shapes. They have also been observed in the wild to have different warning calls, not just for different species of predators, but to be even more specific than that, for example having a different call for individual foxes. This is useful as, like rabbits, these cute rodents have a LOT of predators.

For someone who watches a lot of nature documentaries like me, this featured stuff which wasn’t particularly surprising. The way slugs, wasps and whiptail lizards reproduce is fairly well documented. Many have been shown on other documentaries or seen a lot on the internet, such as Rabbit Island or the goats in a tree.  Some events in this programme felt like filler, like a couple being followed in their boat by a pod of Orcas, what looked like smoke or fog from a distance turning out to be a swarm of midges, a conga line of caterpillas or stoats running around in a strange way and nobody really knowing why.  But the series was still interesting.

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