Gazelle-like antelopes as living flags

Gazelle-like antelopes as living flags

Colouration seeks no camouflage where it advertises safety in numbers.

More...
Perverse exercise for the growing pelican

Perverse exercise for the growing pelican

An exceptional wingspan made resilient by violent nurturing.

More...
Why do mangroves lack fruity succulence?

Why do mangroves lack fruity succulence?

Potassium, the mineral of fruit-juice, can be unaffordable for mere seed-wrappings.

More...
Warning colouration in the giant panda

Warning colouration in the giant panda

The most checkered of bears is the least likely to be worth attacking naively.

More...
The marsupial lion: all slice and no bite

The marsupial lion: all slice and no bite

Unsheath the hidden weapon of an Australian carnivore with desultory canines.

More...
Supermoles despite being marsupial moles

Supermoles despite being marsupial moles

Notoryctids are primitively pouched but at the cutting-edge in other aspects.

More...
Who chose the eyespots on the peacock?

Who chose the eyespots on the peacock?

Peahens were less likely than human protectors to select for these false eyes.

More...
A continent mysteriously empty of tortoises

A continent mysteriously empty of tortoises

Land tortoises failed in Australia not by historical accident but by poor ecological prospects.

More...
Seeing the light for the trees

Seeing the light for the trees

Height of woodlands and savannas is aimed at resources scarcer than sunshine.

More...
How beavers engineered landscapes for bison

How beavers engineered landscapes for bison

Tree-felling, ponding, and silt-damming all eventually produce big grazing.

More...
Trees as green quazi-zombies

Trees as green quazi-zombies

Ponder the resources that really matter under the shade of the energetic living dead.

More...
The hidden power of sea snakes over eels

The hidden power of sea snakes over eels

Why eels can’t defend themselves from being engulfed by sea snakes.

More...
Time did not limit evolution in Zealandia

Time did not limit evolution in Zealandia

Why these are the largest islands without native terrestrial mammals.

More...
Kiwi were no solution to a mammalian vacuum

Kiwi were no solution to a mammalian vacuum

These birds are more far-fetched that even the least likely of furred imposters.

More...
Why external ears are redundant in birds

Why external ears are redundant in birds

A streamlined head is only part of the explanation why birds avoid using external pinnae to locate sounds.

More...
Why elephants defecate wantonly

Why elephants defecate wantonly

Megaherbivore digestion seems inefficient until its cream-skimming tactic is recognised.

More...
What is the real value of a kidney?

What is the real value of a kidney?

There must be good reason why the kidney is twice as energy-intensive as the brain or liver, making it the…

More...
Are birds really avian dinosaurs?

Are birds really avian dinosaurs?

Birds originated from dinosaurs, but equating them with dinosaurs falls off a logical tightrope.

More...
A new vitamin hiding in plain light

A new vitamin hiding in plain light

 Food beliefs have fallen on the buttered side

More...
D stands for delete as vitamin

D stands for delete as vitamin

Calciferol, vital but not vitamin

More...
Coital fanging in a giant cartilaginous fish

Coital fanging in a giant cartilaginous fish

A plankton-siever with only the rudest of Jaws.

More...
Does rickets show clinical deficiency of boron?

Does rickets show clinical deficiency of boron?

Hormonal ossification is elementary.

More...
What lies behind the kidney’s iron curtain?

What lies behind the kidney’s iron curtain?

Where the body ‘earths’ its electrons.

More...
An explanation for sexual skew in the priapiumfish

An explanation for sexual skew in the priapiumfish

Why micro-meta-genitals evolved in fishes.

More...
Can any true bambi weather a desert?

Can any true bambi weather a desert?

What it takes to drought-proof 3-centimetre hooves.

More...
Archaeopteryx is neither a first bird nor a bird in the first place

Archaeopteryx is neither a first bird nor a bird in the first place

The concept "archaeopteryx is a bird" is a dinosaur 

More...
Plumosaurs flew as dinosaurs, not as proto-birds

Plumosaurs flew as dinosaurs, not as proto-birds

Looking past the plumage to see the tell-tale tails.

More...
Fat mephitids not allowed in the Old World

Fat mephitids not allowed in the Old World

A black-and-white case of evolutionary skullduggery?

More...
Authentic mega-killers kept their mouths shut

Authentic mega-killers kept their mouths shut

The mythical snarl of dental sabres

More...
The paradox of the fire-loving crayfishes

The paradox of the fire-loving crayfishes

Building a life on wet combustion.

More...
A thumbs-up on amphibians

A thumbs-up on amphibians

The human hand as living fossil.

More...
The riddle of the failed frogs of Gondwana

The riddle of the failed frogs of Gondwana

Zealandic amphibians are a damp squib.

More...
Why no southern salamanders?

Why no southern salamanders?

The evolutionary compass of amphibian tails.

More...
Frogs are more dexterous than lizards

Frogs are more dexterous than lizards

The simplest frog is more manipulative than the cleverest lizard.

More...
 Frogs' tails hiding in plain sight

Frogs' tails hiding in plain sight

De-tailed amphibians conceal a hiptail of unknown potential.

More...
The dagger looks of golden toads

The dagger looks of golden toads

Black eyes can be poisonous exclamations in orange frogs.

More...
The giant panda as a sinister signboard

The giant panda as a sinister signboard

A black and white warning of dangerous teeth

More...
Arboreal reflections of amphibian eyes

Arboreal reflections of amphibian eyes

The bulging eyes of water and tree frogs differ more than they look.

More...
Frontpage Slideshow | Copyright © 2006-2012 JoomlaWorks Ltd.
Bio-bullets

Divergent adaptations of rock-wallabies and rock hyraxes

Evolution over fifty million years should have shaped the ancestors of rock-wallabies and rock hyraxes similarly. It did not, because of different predators. 

professor caricatureProf. Mumblebard claims: "Rock-dwelling mammals in Australia and Africa have diverged because natural selection, while a valid principle, doesn’t necessarily apply. The ancestors of rock-wallabies and the ancestors of rock hyraxes differed by chance. Given that evolution tinkers instead of re-inventing,{njaccess 2, 3, 4, 5, 6, 7, 8} the exaggeration of these initial differences eventually produced unpredictably different adaptive solutions despite the similarity of their environments." {!njaccess}… See the hidden half of Prof. Mumblebard’s claim by subscribing here{/njaccess}

logoRobin and the Honey Badger respond: "The physical environments of rock-wallabies and rock hyraxes, i.e. rocky outcrops and their associated boulders and cliffs, are similar; but it is the regimes of predation that are different. The discrepancies between the Australian and African mammals are consistent with this difference in predatory pressure and consequently hold true to the principle of evolutionary convergence. Rock-wallabies give birth to embryonic young whereas rock hyraxes give birth to precocial young. Rock-wallabies seem mute whereas rock hyraxes have different alarm calls for various predators. Rock-wallabies can hardly bite whereas rock hyraxes have upper incisors so honed for defence that they get in the way of eating. Rock-wallabies flee bipedally using elastic ricochet and a long tail for balance and keep minimal contact with the rock surface. By contrast, the virtually tailless rock hyraxes can squeeze deep into crevices and flee quadrupedally using swivelling wrists to ensure maximal contact with rock surfaces. All these features are adaptive{njaccess 2, 3, 4, 5, 6, 7, 8} because Australia is far poorer in predators than Africa. Not only is the Australian wedge-tailed eagle less specialised for a diet of rock-wallabies than its African relative, Verreaux’s eagle, is for a diet of rock hyraxes, but leopard, caracal, honey badger and baboons lack counterparts among marsupials. In particular, baboons are so clever and agile that they can harm hyraxes through juvenile mischief as well as opportunistic carnivory. Even if the only additional predator in Australia was a counterpart for baboons, it’s unlikely that animals with the features of rock-wallabies would have evolved in the first place, let alone survived to the present day."

speaker icon"In other words"

{!njaccess}… Reveal the hidden half of this response by Robin and the Honey Badger by subscribing here{/njaccess}


Please join us here at the Bio-edge with your own comments. In the discussion below we encourage links to any evidence supporting either Prof. Mumblebard or Robin and the Honey Badger. Illustrations are welcome but please cite all sources or we may be forced under copyright to delete your comment.

 

Divergent adaptations of rock-wallabies and rock hyraxes

Last modified on 13 July 2015

Comments   

0 #1 Naturapper 2014-02-10 17:20
This clip certainly suggests that baboons will think twice about attacking a rock hyrax. I can’t picture a rock wallaby being nearly as intimidating.

0 #2 Gonzales 2014-02-11 11:59
There is an equivalent in South America? If convergent evolution is credible there is something like hyrax here too. Rock cavy Kerodon is similar but smaller. Perhaps some extinct mammals?
0 #3 BioSkeptik 2014-02-12 16:55
I reckon rock wallabies would do just fine in Africa. It’s just by chance that placentals didn’t evolve that way. As Attenborough himself points out in this youtube clip – they are agile animals and amazingly mobile in amongst the rocks.

www.youtube.com/.../
0 #4 S. Glynn 2014-02-13 10:23
@BioSkeptik. Those wallabies may look agile enough but they’d be dead meat in Africa. Leopards operate at a whole nother level. And baboons have evolved to match leopards in their own way. Have you had the food snatched out of your lap by a baboon flashing in through your car window in a national park picnic site?
0 #5 J. Ordsden 2014-02-13 10:27
It’s pretty obvious that long wallaby tail would be grabbed by baboons or leopards in no time at all…
0 #6 Zoophile 2014-03-06 13:19
It’s so easy to take it for granted that hyraxes and baboons live together, without thinking of baboons as an environmental force. It is interesting to wonder what the hyraxes lives would be like if the baboons weren’t part of the scenery. Wish I’d thought of that.
0 #7 Wildman 2014-03-06 14:02
I can’t see a rock wallaby topping this! :-)



Now there’s some suction-footed agility to stay safe from African predators.

You have no rights to post comments