|Pokémon's fourth generation brought us a number of additions to gameplay. Alongside major advances like global online trading and the physical/special split, the games also introduced more subtle developments, like gender differences. In nature, animals of opposite genders frequently look quite different. This is called sexual dimorphism, and I was very glad to see this incorporated into the games. There was one problem, though: previous generations had depicted different genders as identical to each other (with the exception of Nidoran), so it seems Game Freak were reluctant to make these new differences too obvious for fear of contradicting earlier games. As a result, the Pokémon games' equivalent of sexual dimorphism is expressed via quite subtle, often barely noticeable differences.
Chinchou, the Angler Pokémon, and Lanturn, the Light Pokémon
And this is a shame, really, because there are many real life creatures with fascinating gender differences that have also inspired Pokémon. We'll meet such a creature today: an ocean-dwelling predator with a highly original method of catching its prey.
Chinchou and Lanturn are based on anglerfish, an order of fish made up of hundreds of species showing a great deal of variety. Some like the open ocean, while others dwell near the ocean floor... but they all share the same system of predation. Anglerfish all have at least one fin that has grown into a long, overhanging 'lure', called an esca, that dangles above their head. This can be articulated and moved around so that it resembles a small fish. Other fish are drawn to what appears to be a free meal, and usually end up becoming a meal themselves. Anglerfish have enormous mouths and can easily swallow their prey whole, while their teeth are angled inwards, allowing prey to swim into their mouths, but preventing them from escaping.
It seems that Chinchou and Lanturn have taken particular inspiration from the deep sea species of anglerfish. One clue to this is their illuminated escas: at the bottom of the sea, there is very little light, and so the anglerfish must produce their own light via a process called bioluminescence. In order to do this, they have developed a symbiotic relationship with bacteria. Millions of tiny, glowing bacteria make their home in the anglerfish's esca, their light drawing prey towards it.
Deep sea anglerfish also tend to have unusually round bodies, a trait that can be seen in both of these Pokémon, particularly Chinchou. A compressed body reduces a creature's surface-to-volume ratio, which is useful for minimizing exposure to a harmful environment. On the ocean floor, anglerfish must contend with high pressures and low temperatures, and their compact shape reduces the effects of pressure while reducing the amount of body heat that they lose.
Yet another feature reminiscent of deep sea anglerfish can be seen in Chinchou's design: it appears to have small 'feet', and has even been seen using them to walk in the anime. Many anglerfish that live on the sea floor have evolved ventral and pectoral fins that also mimic the function of feet, allowing them to walk along the surface.
, the humpback anglerfish. In this species, females are eight times larger than males.
Curious as these things are, they pale in comparison to the extreme sexual dimorphism exhibited by many anglerfish. The Ceratiidae, one of the commonest families of anglerfish, presented a unique problem to scientists that set out to study them. All of the specimens that they could find were female, and there simply weren't any males to be found, or so it seemed. Additionally, many of the females seemed to have small parasites attached to them. The solution to the puzzle was a surprising one: the parasites were actually the missing male anglerfish!
As it turns out, Ceratiidae exhibit immense differences between the genders. Some female Ceratiidae can reach four feet in length, while a male of the same species might be just four inches. The males look very different, too: they have slight, elongated bodies in comparison to the bulky females, and don't possess either lures or large jaws for catching prey. The males attach themselves to a female and then release an enzyme that causes their bodies to fuse together. Their blood supplies merge, meaning that the male can remain permanently attached to the female, without any need to hunt for itself. Gradually, the male's body dies off, until only the sexual organs remain. The female will now have access to these whenever she decides it's time to mate.
If this sounds like a bizarre arrangement... well, it is. But it also seems to have evolved for a reason. In the deep sea, finding a mate can be difficult, due mainly to the lack of light at such depths. Male Ceratiidae have developed an extremely acute sense of smell, allowing them to seek out females. And so, once the male discovers a female, it will latch on and never let go. The male's comparatively small size makes this process easier, since the female can still swim quite happily with a much smaller male attached to her. This system has become so fundamental to the fish that mature males actually lack a functional digestive system, meaning that their only hope for survival is to latch onto a female and obtain nutrients directly from her bloodstream.
Now, while it's not in my nature to describe any creature as 'ugly' – no, not even these – it's obvious that Game Freak decided to prettify the anglerfish somewhat upon turning it into a Pokémon. They still bear many similarities to their inspirations: both Chinchou's English name, as well as its Japanese name, Chonchie (チョンチー) are derived from chouchin-ankou (チョウチンアンコウ), a term referring to anglerfish of the Himantolophidae family. But it can't be denied that Chinchou and Lanturn look more like the cheery stars of a Pixar movie than the deep sea horrors they're actually based on. Anglerfish could just as easily have been turned into a more sinister Pokémon along the lines of Carvanha, and I wonder if, at some point in the future, we might see another family of anglerfish that draws more heavily upon their spookiness.