The page cannot be found

Species of animals change over time, some just a little but others quite a lot! Science took a while to catch up but in 1858 the idea of Natural Selection was put forward.  We have Charles Darwin and Alfred Russell Wallace to thank for that, because it’s been around ever since. Soon after, Darwin would publish “On the Origin of Species” in 1859, a book that shook educated society to the core. In fact, the theory of evolution was not taught in many schools because people disagreed with it - and there is still some dissent today (in some places!).

But how does natural selection work?  This hugely interesting video from the Natural History Museum in London takes the giraffe as an example. We know how well suited they are for survival, especially because of their long necks and tongues that help them pick off the juiciest leaves from even the tallest of trees.  They didn’t always have long necks and tongues – and the changes that happened to make it so are called adaptations. There is also the fact that every single member of one species is just a little different from all the others – and that’s called variation. This variation can sometimes mean that certain individuals have an advantage over others in their natural environment.

So, natural selection happens because animals with adaptations that make them  more successful are way more likely to survive long enough to produce offspring who will have the same adaptation.  SO, that’s why if you go back far enough, and encountered the ancestor of today’s giraffes, you will probably have great difficulty in recognising it as such.  To learn more about variation, adaptation and natural selection, look at the video below. It’s put forward in a very straightforward way which makes you wonder why it too so long for us to get to Darwin and his ideas.  I guess something is only obvious when it’s made obvious.

Some frogs spend their lives in the tree canopy and only come “down to earth” when it’s time to find a mate and breed.  They can live in the treetops because the environment is so humid that they do not have to rely on puddles or pools to get by. That is the case with the gliding leaf frog, and the way it gets itself back to the ground is quite spectacular.   The gliding tree frog (also known as the gliding leaf frog) is endemic to the humid forests of the tropical east pacific, in countries including Costa Rica, Panama, Colombia, and Ecuador (but not spread throughout these countries).

They have huge webbed feet – and that’s just as well.  They use them, effectively, as parachutes.   Once they get to the ground the males begin to sing – to attract the females. This fills the surrounding forest with noise – so it is the female who makes the ultimate choice of which male she wants to mate with.   She always seems to go towards the loudest calls – this generally means a bigger frog! However, in order to get to her choice, she has to get past the other frogs who want to get overfriendly with her… and so she sometimes has to use her very large feet to kick unwanted suitors away. That is more difficult than it sounds, given that once attached, the male frogs are almost impossible to remove.

Watch some amazing footage of the gliding leaf frog in the video below.  To be honest, it looks like something of a free for all!

Although there are only a fraction of the suburban hedgehogs in the UK that were around even twenty years ago, life must go on.  This clip from the BBC documentary Secret Gardens shows a female hedgehog looking for a mate.  She really does have to search far and wide in order to find a mate, but eventually she succeeds!  This is a sweet story but sad too, as it underlines just how few of these lovely, harmless creatures are left in the towns and cities of the UK.

Perhaps, as is featured in the video, more effort should be put into creating hedgehog corridors, so that they can safely navigate routes between properties in order to find the love of their life (well, of the evening at least).   A little patience and a little help can go a long way – and it would be great to think that hedgehogs are considered when new houses are built too.  Sometimes, one has to wonder why people even build houses with gardens – they are in such a rush to pave them over that it is little wonder that the hedgehogs of England are becoming something of a rarity.

Did you know that 7.5 billion landbirds currently call North America home?  That’s an awful lot of birds, but here is a question – think about it.  When did you last see a dead bird?  The adult  mortality rate of songbirds is around 45% in their first year, so why is it we don’t see many (or any) dead birds?  So, what happens to birds when they die, when they fall off their metaphorical perch?

It seems that behavior changes when a bird senses that it is not long before it slips off its mortal coil.  They become lethargic and seek cover.  When a bird knows that its health is compromised it retreats to places where predators are unlikely to spot it.  It is an instinctive threat response – to hide because it even though it is on its way out, it still doesn't want to be killed by a predator.  So birds die in places that you can’t see into - dense foliage often covers them up after death.   Even if the bird dies in plain sight, the average time it is visible is about 30 minutes to 4 hours.  Scavengers get them. As well as insect action, cats and even other birds can come along and pick up the carcass.  Watch this fascinating video by Bird Whisper, which delves into more detail below.

This gorgeous bird is a brood parasite (like most other cuckoos), meaning females lay their eggs in the nests of other bird species. The picture is of a male (he has a bright yellow breast). During the rainy-season breeding period between September and March, a female can lay about 19 to 25 eggs. Although they do not need territory to raise chicks, male cuckoos still defend territories to attract mates. The species is widespread across sub-Saharan Africa. Image

Animals that are cave specialists are known as troglobites and can be counted as the most specialist species in the world – one species of angel fish troglobites lives only in two small cave waterfalls in Thailand.  To say that they have a precarious grip on survival in this day and age is putting it mildly.  Many of these species have lost the use of their eyes altogether as the sun never penetrates their cave dwellings. However, to become troglobitic can take thousands of generations. 

This fascinating video from BBC Earth, narrated by Sir David Attenborough looks at troglobites in general – those who have lost the pigment in their skin and also their eyes.  However, to compensate for their blindness, creatures like the Texas Blind Salamander has other senses fine-tuned to compensate for their lack of sight.  Take a look at this video – and discover more about the strange cave-dwelling species, who somehow manage to survive despite the odds being massively stacked against them.

This morning, as I walked to the shops, I spotted a crow.  That wasn’t hard because it was making a loud cawing sound – a proper South East London crow, indeed.  Perhaps there was a cat around, maybe it was trying to locate its mate, or it could have been defending its territory.  I’m not sure what was going on, but one thing was for sure – this crow was perched very precariously on a sapling in a planter.  Perhaps six foot tall, the young tree has been damaged (perhaps by the crow?), meaning that a bird, if it lands elegantly enough, can perch atop it.  Yet what bird would want to do that? This one, obviously.  I didn’t see it land, but the level of expertise it must have taken is astonishing.  I say this because I can’t even do a three-point turn very well, so I can’t imagine calculating angles with height involved too.

Still pondering these avian acrobatics, I reached home and popped the eggs I had just bought into the fridge. I discovered a single egg at its back, and I decided that, since the crow had given me a visual treat, I would give the ones that haunt my garden an edible one. Now, this isn’t something I do often.  Although I do like to see the bigger birds in my garden (the rivalries between the crows and the magpies are legendary for their riotousness, noisiness and general length!) I generally do not feed birds at all. I used to, but then read up on it and discovered that it could produce an over-reliance on feeders, not to mention that lots of birds congregating together isn’t necessarily good for their general health.

Some species don’t need males.  Take the New Mexico Whiptail Lizard for example.  There are no males in this species. So, of course, the sensible question to ask is how do they reproduce?  They use something called parthenogenesis which involves no males and no sperm.  The female can produce an egg all by herself.  The eggs will produce an all-female brood, clones of the other – who will go on to… you get the point.  While this does allow some species to rapidly increase their range, it does somewhat limit the genetic diversity of the species!

For a closer look at parthenogenesis, take a look at these videos created by the Natural History Museum in the UK.

Did you know that a health queen honey bee can lay up to 2,000 eggs a day in the peak season?  That is one busy queen – and running the whole colony on top of that must sap her strength somewhat.  But wait a second – does a queen bee actually run her colony?  That is what most people would naturally assume, but they would be wrong.  She doesn’t make any decisions about what goes on in the hive, she simply secretes a pheromone that reassures the other bees that she is still around and healthy to boot.  If she stops producing the pheromone the colony would quickly become chaotic.  The worker bees that make up 99% of the colony and they are really the ones who keep the colony together, through a variety of tasks that they do throughout their lives.

There is a strict hierarchy in a hive and that includes not just the workers, but drones too. These are the only males in the colony and – unfortunately for  them – they get thrown out of the hive when times get hard.  I suppose having one job (mating) is a plum one when times are good (except for one gruesome fact!). Find out all about bee hierarchies in this fascinating video.