| Seeing Is Believing (i)
Genetic Throwbacks - tails in humans
ie. evidence that our distant ancestors possessed tails
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See,
see again,
and Believe |
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From Field Guide To The Snakes and Other Reptiles of Southern Africa,
Bill Branch, 1988 |
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Armed and dangerous
The discovery of a chimpanzee making and using a spear in
Senegal is not only a surprising revelation about our nearest evolutionary
relative, say Mairi MacLeod and Ian Sample - it could also provide
invaluable insights into how man developed technology
Mairi MacLeod and Ian Sample
Friday February 23, 2007
Guardian
In the dry heat of the west African savanna, a chimp called Tumbo hauled
herself up into a wizened tree. She had spotted something: an
interesting-looking hole at a fork in the trunk. Watching her, researcher
Paco Bertolani suspected that she was looking for insect larvae to eat; the
chimpanzees had done this before. Tumbo grabbed a thin branch, snapped it
free and purposefully honed one end, using her teeth to make a point. Then,
she moved closer to the hole, grasped the primitive spear, and rammed it
inside with as much might as she could muster. Afterwards, she pulled it out
and sniffed and licked the end. Tumbo repeated the violent stabs again and
again until, apparently satisfied, she moved across to a withered branch
adjoining the trunk and leapt up and down to break it free. From within the
now exposed hole, she retrieved an unmoving bushbaby, evidently dead as a
result of the onslaught. She sat down and calmly dismembered the animal,
chewing on the meat with relish and accompanying her meal with odd handfuls
of fresh leaves.
Tumbo is the first chimpanzee to be seen making and using a tool to hunt for
meat. Details of her spearing her prey are revealed for the first time today
in the journal Current Biology. Such behaviour has never been seen before,
and it represents an important leap forward in our understanding of just how
sophisticated chimpanzees - humankind's closest relatives - really are.
There was a time when scientists believed that one of the major differences
between us (humans) and them (animals) was tool use. But those days are long
gone. Last year, chimps in the Congo were captured by hidden video cameras
using stick tools to dig and dangle for termites. Earlier this month, a crop
of ancient stone tools dating back 4,300 years were unearthed and identified
as having been used by chimps, fuelling a debate about a chimpanzee Stone
Age and the chance that both chimps and early humans inherited tool use from
a common ancestor. Now there's Tumbo using a spear.
We have certainly come a long way since a young Jane Goodall began her
inspirational research into chimpanzee behaviour at Gombe in Tanzania in the
1960s, back in the days when chimps were seen as innocent, peace-loving
creatures (since then, they have been observed hunting down monkeys in
coordinated groups, not to mention murdering each other). Increasingly,
chimp behaviour is being found to be so human-like that it is giving
scientists invaluable insights into the evolution of early humans.
"Technology is one of the most important aspects of the human condition.
It's the reason we've conquered the planet, but it had to come from
somewhere," says William McGrew, a primatologist and expert on the evolution
of material culture at Cambridge University. "Short of inventing a time
machine, the next best thing is to look at our nearest living relations and
their technology." According to McGrew, evidence from the archeological
record suggests that our hominid ancestors started using tools in hunting
around 400,000 years ago in Europe. "And what do you think [they used]?" he
asks. "Sharpened wooden sticks. It is essentially the same weapon that's
being used by these apes, except it's bigger."
But why has spear-making by chimpanzees never been seen elsewhere, despite
decades of research? The reason could be that chimp behaviour in this
particular habitat - the hot, dry savanna of Fongoli in Senegal - has not
been studied in detail before. Chimps adopt different strategies in
different environments: complex cultural differences have emerged between
populations. And the Fongoli chimps do seem to be quite an unusual
population. As well as using spears, they have taken up residence in a
number of caves, worn from rock by millennia of flowing water. It seems they
like to use them for picnics and siestas, or to shelter from the heat during
the day.
Bertolani, of Cambridge University, who is collecting data for his PhD, once
spent the day with Fongoli chimps in one of their more open caves and
witnessed events not out of place in a soap opera. He says some rested and
groomed, others quarrelled, while males showed off, running in and out of
the cave for the benefit of a female. Others did their best to ignore the
spectacle and carried on sleeping in the dark recesses. Researchers have
also witnessed the chimp equivalent of a pool party - with no little
astonishment, because chimps usually have a strong aversion to water.
"Chimps are reckoned to be hydrophobic, because they sink like stones," says
McGrew. "Then along come the Fongoli chimps, who, when the rains come in May
and fill up the depressions in the plateaus, jump in and sit there up to
their chests, all crammed in together."
"They run through and splash each other and display," says Jill Pruetz,
director of the Fongoli project at Iowa State University.
One of the most intriguing things about the Fongoli spear use is that it is
females who do the hunting. Monkey hunts by chimps are well documented, but
they are dominated by the big males. Although females occasionally take part
in hunts, it's normally a back-seat role. Charging through the trees is
dangerous, especially with a small infant, and even if a female catches the
quarry, there's a good chance she will have to surrender it to a larger
male.
Pruetz says females and youngsters are forced to innovate to get protein for
their diets; her point is that it is females who are driving the adoption of
new technology. "The females and maybe the young males too are basically
having to solve problems in a creative way because of competition with adult
males," she says. "That may be by technology, and not by brute strength or
force."
"Basically, you can spot that tree hole and you can creep up and take a good
look," says McGrew. "You can do that even if you're encumbered with an
infant, and because it's a solitary activity, you don't have to coordinate
with others."
The researchers say spear use in Fongoli is performed almost exclusively by
females and youngsters. In spite of the fact that the researchers were
concentrating on male behaviour during their study, they saw only one
attempt at spear-making by an adult male out of a total of 22 episodes.
"[This] strengthens the case that in all likelihood the origins of
technology [in humans] were with females," says McGrew.
The chimpanzees at Fongoli have been habituated to humans for less than two
years. In that short time researchers have discovered a wealth of new
chimpanzee behaviour. What else are these apes going to surprise us with?
Pruetz says she is learning to expect the unexpected and is hoping that it
will be possible to keep the research going at Fongoli far into the future.
So we know now that chimps are skilled and cooperative hunters. We know they
are capable of terrible violence, but also empathy and, according to some
observers, even primitive morality. We see the roots of human behaviour in
wild chimpanzees today: they are on a behavioural continuum with us. But how
far, if anywhere, will their technology go? Humans achieved great leaps in
technology only after millions of years of environmental pressure gave rise
to more complex brains.
"Chimps do a pretty good job of tackling their problems without developing
technology. What's instructive is when they need it," says McGrew. Chimps
have the advantage of big, strong jaws and teeth, he says, so they can
accomplish many of their jobs without tools. But, he says, "even after human
technology took off, it took millions of years to get notable changes, so
for us primatologists to be lucky enough to see anything in a couple of
decades is highly unlikely. Every one of us would love to be on the scene
when there's an important advance in chimp technology. It hasn't happened
yet, but we live in hope."
But we might not get the chance. Chimp numbers are in freefall as a result
of illegal trapping, hunting for bushmeat and deforestation. Just as we are
beginning to truly appreciate just how amazing the abilities of chimpanzees
are - how they mirror us in so many ways, yet are also intriguingly
different - we're busy wiping them out.
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Wild things: the weirdest facts from the animal kingdom
Did you know that trout fake orgasms, or that frogs swallow
with their eyes? Matt Walker scours the latest zoological research to find
the interesting facts
The Independent
04 October 2006
SEX BY SURROGATE
A male flour beetle (Tribolium castaneum) can mate and impregnate a female
he has never met. No other animal is known to have sex by proxy in this way.
Many males often mate with each female. The first male will deposit sperm in
the female, then a second will arrive and use its spiny genitalia to scrape
out his competitors sperm, before mating itself. Much of the sperm of the
first male is carried unwittingly by the second male on its genitalia. One
in eight females are fertilised by proxy.
HOW WAS THAT FOR YOU?
Female brown trout (Salmo trutta) fake orgasms to encourage males to
ejaculate prematurely. By doing so, they dupe their partner into thinking it
has successfully mated, before the female fish moves on to find a better
male with which to do the real thing.
MONKEYS MIX THEIR DRINKS
Given the choice of whether to have an alcoholic beverage, or something
alcohol free, around in one in 20 vervet monkeys (Cercopithecus aethiops)
become instant binge drinkers, gulping down so much booze that they
eventually pass out. Around one in seven are heavy drinkers who like their
spirits neat, while most are moderate drinkers who prefer to wash down their
alcohol with a little fruit juice. Just one in seven decide not to drink at
all.
BACH IS BEST
Java sparrows (Padda oryzivora) appear to prefer the music of some
composers. Sparrows will listen longer to music by Bach than by Schoenberg,
and prefer Vivaldi to Elliott Carter.
MAKE ME CRY
There are moths that drink the tears of elephants. Tears contain salt, water
and trace levels of protein. Mabra elephantophila steals the tears without
the elephants seeming to notice. Lobocraspis griseifusa does not wait for an
animals eyes to moisten - it sweeps its proboscis across the eye of its
host, irritating the eyeball, encouraging it to produce tears.
GIVE ME BLOOD, AND MAKE IT FRESH
Dracula ants (Adetomyrma venatrix) suck the blood of their young. Queen
Dracula ants live in Madagascar, cut holes in their own larvae and feed upon
the haemolymph, or insect blood, that oozes out.
TASTED GOOD, I THINK
The star-nosed mole (Condylura cristata) is the fastest-eating mammal in the
world, capable of wolfing down a snack of worms in 227 milliseconds. It uses
22 pink fleshy tentacles that adorn its face, each highly sensitive to
touch.
DONT SWIM AND EAT
European eels (Anguilla anguilla) will not eat at all during their long
migration to the Sargasso Sea.
SUPERSIZE ME
A female hippopotamus (Hippopotamus amphibious) can eat more food relative
to its body size than any other ruminant. Its stomach contents can make up
one quarter of its total body weight.
THAT FLOATING FEELING
Seals hold their breath while sleeping on the surface of the water.
SHOOT ME, SEE IF I CARE
Tardigrades, eight-legged animals that are nicknamed water bears, are the
hardiest creatures on earth. The tiny organisms, up to 1.2mm long, are
capable of withstanding the most extreme environments by dehydrating and
going into a state of frozen animation. There is anecdotal evidence that
some can survive being immersed in liquid helium, just 1C above absolute
zero. They can withstand being boiled in water, thrown into pure alcohol,
and a pressure of 600 mega-pascals (six times the pressure of sea-water at a
depth of 10,000 metres).
NATURAL AQUALUNG
One species of spider spends its life underwater. Using a dense mat of
specialised hairs that covers its body and abdomen, the water spider (Argyroneta
aquatica) traps a bubble of air around its body, breathing the trapped air.
WHO NEEDS SATNAV?
Wandering albatrosses (Diomedea exulans) can pinpoint the specific remote
island where their nests are located after making foraging flights of
several thousand kilometres of featureless ocean. They do not rely on the
earths magnetic field, and no one knows how the birds acquire such precise
and impressive navigation ability.
TOOTHSOME FARE
The cookie-cutter shark (Isistius brasiliensis) measures only 50cm in
length, yet has been recorded taking chunks out of the rubber sonar domes of
nuclear submarines with its razor-sharp teeth.
HONEY, THEY TOOK THE KIDS
Adult emperor penguins (Aptenodytes forsteri) attempt to kidnap the chicks
of another breeding pair. They forcibly wrestle the juvenile away from its
parents, who try to protect the chick by fighting back. Kidnapping often
occurs when a penguin that has failed to breed sees a chick begging its
parents to be fed, and interprets the juveniles behaviour as a cue to
parent it.
FATAL ATTRACTION?
A female house sparrow (Passer domesticus) will often seek out the nest of
another female that her partner has also mated with. She will then kill the
first females young, to remove the competition and ensure that the male
spends as much time as possible helping to raise her chicks.
GRUBBED OUT
The caterpillar of the large blue butterfly settles beneath its food plant
to await discovery by red ants (Myrmica species). By secreting hydrocarbons
that mimic those made by Myrmica, the caterpillar tricks a foraging worker
into taking it into the nest, where it is placed among the ant grubs. The
caterpillar then moves to safer chambers, returning periodically to
binge-feed on ant grubs.
SLAVERY ON SIX LEGS
Some ant species make slaves of others. Those in the subfamily Formicinae
will go out and raid the nests of other species nearby, and steal their eggs
and pupae. These are taken home, when the resulting young are raised as
slaves, having to do all the foraging, cleaning and babysitting for their
masters.
TIME TO BALE OUT
Certain species of canopy ant jump out of trees to escape being eaten. When
Cephalotes atratus is approached by a predator it throws itself into the
air, orientating its body to steer into a steep glide and head for the lower
reaches of the tree trunk. On average, 85 per cent of all ants that take a
leap successfully land back on the tree.
MARAUDING MUSSELS
Mussels can be voracious cannibals. At certain times of the year, up to 70
per cent of all food eaten by the green-lipped mussel (Perna canaliculus) is
the larvae of its own species.
TRY THIS ON FOR SIZE
Uloboridae spiders wrap their victims to death. An individual small uloborid
spider (Philoponella vicina) will weave more than 140 metres of silk to wrap
a moth or beetle. It binds the silk shroud so tight that it compresses the
preys body, breaking the insects legs, buckling its compound eyes inwards,
and often killing it outright. Spiders of the family Uloboridae have lost
their fangs, forcing them to evolve their vice-like death shroud.
MURDEROUS MOGS
In the UK alone, domestic cats kill 57 million mammals a year, 27 million
birds and 5 million reptiles and amphibians.
STOP AND YOU DIE
Swarms of Mormon crickets (Anabrus simplex), which in the United States
reach up to 10km long, keep on the move not just to find food, but to avoid
being eaten by each other. If an individual stops for any reason, it is
likely to be devoured by some of the millions of its following brethren.
THE HOUDINI CHALLENGE
The parasitic gordian worm (Paragordius tricuspidatus) begins its life in
water before infecting the body of a larger insect host: a cricket. But the
worm has a remarkable ability to survive even if its host is eaten by a
larger predator. When the cricket is eaten, and partially digested, the worm
escapes by burrowing through the body of the predator, usually a fish or
amphibian, until it emerges unscathed in the water, where it continues its
life cycle.
WOULD YOU LIKE EYES WITH THAT?
Animals usually swallow using their tongue and throat. The northern leopard
frog (Rana pipiens) uses its eyes. To swallow food such as a small cricket,
it closes its eyes and retracts its eyeball into its body. These push into
the pharynx and against the prey item, and regular retractions help force
the food to the back of the oesophagus.
THE BIG CELL
The yolk in an unfertilised ostrichs egg is the largest single cell found
in nature.
WERE JUST DOWNSIZING
The Galapagos marine iguana (Amblyrhynchus cristatus), the only sea-going
lizard, is also the only vertebrate known to shrink in body size regularly
when adult, and then to grow larger again. The iguanas shrink up to 15 per
cent in body length during El Nio weather events, losing bone mass. The
following year the iguanas grow even larger before shrinking again.
SEEING IS BELIEVING?
Tarsiers, a primitive group of primates, have eyeballs bigger than their
brains.
CANT HELP THE WAY WE FEEL
Some genetically engineered mice have have hearts that glow green every time
they beat.
SAFE CRYOGENICS
The wood frog (Rana sylvatica) freezes solid during the winter before
thawing out as the temperature rises in spring. The frog has a unique
physiology that prevents damaging ice crystals forming within its cells.
COME FLY WITH ME
The elusive paradise tree snake (Chrysopelea species) is the only vertebrate
that can fly - despite having no limbs. The snake is a true glider, defined
as covering a greater horizontal distance than it falls vertically. First
the tree snake leaps from a tree into the air, and adopts an S-shape,
changing its body shape to that of a biplane. Then the snake undulates its
body, and while no one can be sure why it does this, the changing posture
might serve to move its centres of gravity and the flow of air pressure in a
way that allows controllable flight. It can achieve a glide angle of just 13
per cent to the horizontal (90 per cent constituting free fall) and cover
distances of 20 metres.
WHALE OF A TIME FOR BABIES
For the first month of their lives, newborn killer whales (Orcinus orca) and
bottlenose dolphins (Tursiops truncatus) do not sleep but remain mobile for
24 hours a day - as do their mothers.
EAT ME, BABY
A worm-like amphibian, the caecilian (Boulengerula taitanus) takes parenting
to a new level. By elongating specialised stratified epithelial cells,
mothers transform their skin until it is twice as thick, and it is then
eaten by their offspring.
PETER PAN SYNDROME?
Many tadpoles of the African clawed frog (Xenopus laevis) never turn into
frogs, instead growing into giant, grossly deformed tadpoles with a
hunchback, on average four times longer and up to 50 times more massive than
normal tadpoles. They can survive for years, although they cannot reproduce.
CATCH US IF YOU CAN
Cuttlefish (Sepia officinalis) change colour almost instantaneously to mimic
the rock or seaweed of the seafloor against which they are hiding. They do
so while being completely colour-blind.
HOME IS BEST
In 25 years of intensive research watching a group of killer whales (Orcinus
orca) in the coastal waters of the north-eastern Pacific Ocean, there has
not been one documented incidence of a male or female offspring leaving
their mother. Each baby grows up and remains within the family group for the
rest of their lives.
CANT SWIM? NO PROBLEM
Fire ants (Solenopsis invicta) survive floods by clinging together in huge
numbers to form large rafts.
Moths that Drink Elephants Tears and Other Zoological Curiosities, by Matt
Walker, is published by Portrait, 9.99.
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Evolution of the Eye
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