Hey, I'm Jess Keating, and you're watching Animalogic: Second Nature.
[male announcer] Is there a black sheep
in your family? There are four in
Elaine Knutson's. The 12-year-old 4-H girl
from Petaluma, California, is raising quadruplet lambs,
two boys and two girls, all black.
[♪♪♪] [Jess] Melanism is an adaptation
that serves two purposes. It increases an animal's
chance of survival and it makes it look awesome.
[♪♪♪] Animals with melanism have
an elevated level of melanin, a skin and hair pigment,
and this condition can often improve
the animal's camouflage. [male announcer] Black is then
added to give tonal value and depth to the colours.
Colour strongly influences
our daily lives. It can appeal to us pleasantly.
[Jess] Prey species, like melanistic
eastern grey squirrels, becomes less conspicuous
to predators. While predators,
like the melanistic leopards, become more effective
ambush hunters. Melanism occurs in hundreds
of different species. For felines, the most popular
melanistic species is the black panther
which are really melanistic leopards or jaguars.
Though melanism does occur in several other cat species,
including the serval, domestic cat, and a few others.
Leopards are nocturnal animals, so being darker in these
dark environments makes them almost
impossible to spot. Melanism occurs in about
11% of the leopards range, but the vast majority
of black panthers are found in the dense
tropical rainforest of India and Southeast Asia.
In some areas of the Malay Peninsula,
almost all leopards are melanistic.
In the exposed savanna, virtually all leopards
are spotted. The gene for melanism
in leopards is dominant, so even if a panther mates
with a spotted leopard, their babies are likely
to be panthers. Melanistic jaguars are more rare
and only occur when both parents are melanistic.
But if you're lucky enough to encounter one,
it will probably be one of the most beautiful animals
you will ever see. The melanistic form of the
red fox is the silver fox. They used to be
relatively common, but over hunting has reduced
the proportion of the population that's melanistic.
Records from the Hudson's Bay Company
show that up to 25% of the fox pelts
traded in British Columbia were silver.
Their pelts were more valuable than red pelts,
which gave trappers an incentive to target them.
Because of this, only about are silver.
In squirrels, melanism is rare with only about one
being totally black. This is caused
by a recessive gene and only a pair of
black squirrels can mate to make melanistic babies.
[male announcer] This is what you might call
a squirrelly story.Meet Ms. Florence Hinton of Grover City, California,
who has trained a small platoon
of the bushy-tailed little rodents into
amiability and a desire to please. Snookums here is a motherly
little old lady squirrel with quite a talent
for babysitting. [Jess] Their colouration
seems to be an adaptation for life in dense forests
as a way to be less conspicuous to owls and other raptors.
Despite this, there are some urban areas where they thrive.
My home town of Toronto, Canada,
has one of the largest concentrations
of black squirrels in the world. Several other rodent species
like marmots and mice have similar melanistic
fashion sense. Melanism can be
caused by human activity. This is known as
industrial melanism and is one of the best examples
that we've witnessed of natural selection in action.
Industrial pollution kills lichens in trees
and creates a lot of soot that builds up everywhere.
This makes lighter individuals stand out more
against their background and the darker individuals
more likely to survive. A particularly good example
of this is the peppered moth. At the beginning
of the 19th century, there were no records of
melanistic pepper moths. They were all mostly light grey,
but when the industrial revolution kicked in
black peppered moths were reported.
Their numbers increased rapidly, and by the end of
the 19th century, 98% of peppered moths
were black. Then as environmental
regulations were enacted and soot deposits washed away,
the lighter moth recovered. are mottled light grey.
[male announcer] This girl's hair looks light when we see her between
two dark-haired girls. But if her companions
are light blondes, the girl in the centre will now
impress us as having dark hair. [Jess] Industrial melanism
and a few beetles, but it's not the only reason
some insects are melanistic. There is a positive correlation
between insect melanism and pathogen resistance.
Insects that live in high density populations,
such as spodoptera moths, need to develop
stronger immune systems. One of the ways
they do that is by beefing up
their phenoloxidase system which kills or
neutralizes pathogens by bombarding them with melanin.
As a side effect, a higher portion of them
are born melanistic. In birds, melanism is rare, but melanistic penguins,
owls, and quails, among others, have been reported.
My two favourite melanistic birds by far
are the black silky rooster and the ayam cemani.
Both of these domestic fowl are not only black on the outside,
but also black on the inside. [man] See the eyes?
The eyes is very black. Can you see the tongue colour?
It's black. You have to make sure
that everything is black. Thank you.
[Jess] Their beaks, waddles, combs, tongues, bones,
and even organs are all jet black.
Their black colouration makes them
much more attractive to breeders,
and so their hyper pigmentation indirectly
has led to higher chances of producing offspring.
[Rooster crowing] [Jess] While cemanis
are quite rare, black silkies are very popular
and known for being super docile and are sometimes kept as pets.
And in case you're wondering, there are no known cases
of melanistic humans. But there are lots of animals
and humans with the opposite condition,
albinism, but that's a conversation
for another week. The [inaudible] here is
you don't actually believe you saw a [inaudible], do you?
So what should I talk about next?
As always, please let us know down below in the comments,
and don't forget to subscribe for new episodes every week.
Thanks for watching. [♪♪♪]