The Colugo Challenge
Perfectly fit for its life in the trees, the colugo just doesn’t ‘fit’ into the evolutionary ‘tree of life’
Posted on homepage: 25 June 2012 (GMT+10)
Despite the colugo’s inconspicuous existence and nocturnal habits—gliding silently from tree to tree high in the tropical rainforest canopy—this reclusive leaf-eating mammal of Southeast Asia has certainly stirred evolutionists.
That’s because the colugo just doesn’t ‘fit’ the supposed ‘evolutionary tree of life’.
Sir David Attenborough, narrating a BBC documentary, said,
“It’s a colugo or ‘flying lemur’, though this is something of a misnomer, as it doesn’t actually fly, and it certainly isn’t a lemur. In fact, nobody’s quite sure who its closest relative is.”1
As in other gliding mammals, a thin gliding membrane or patagium extends from the colugo’s body to the limbs. But there are striking differences between it and other mammalian gliders, which are either rodents (order Rodentia, e.g. the flying squirrels of America and Eurasia) or marsupials (order Marsupialia, e.g. the flying phalangers, sugar gliders and feathertail possums of Australia and Papua New Guinea). Colugos are neither. They are the only members of the “obscure and tiny”2 order Dermoptera—‘skin-wings’.
The colugo’s large patagium gives it a wingspan of up to 70 centimetres (27 in)—the size of a large doormat. Also, unlike the other gliders, the membrane embraces nearly the entire body margin, extending to the tail, limbs and tips of the fingers and toes. This webbed space between fingers and toes is why evolutionists for some time thought they could place colugos somewhere ‘near’ the ancestor of bats on the ‘evolutionary tree’. Outspoken evolutionist Richard Dawkins (trying to explain how neo-Darwinism might bridge the mind-bogglingly huge gap between non-flying and flying animals) wrote in his 1996 book Climbing Mount Improbable:
“My guess is that both bats and birds evolved flight by gliding downwards from the trees. Their ancestors might have looked a little like colugos.”3
Evolutionists at that time thought that “an early branch of the ‘primate’ tree gave rise to the megabats via the intermediate, gliding dermopterans”4—i.e. from colugos came bats.
However, by the time Dawkins wrote The Ancestor’s Tale (2004),5 new evidence had come to light which forced evolutionists to abandon the earlier colugo-to-bat idea.6 Instead, they were now seeking to link colugos with tree shrews (order Scandentia) and primates (order Primates). Dawkins refers to the change-of-mind leading to this supposed ancestral ‘rendezvous’:
“A few years ago, the colugos would not have entered into this picture. Orthodox taxonomy would have had the tree shrews alone joining the primates at this rendezvous: the colugos would have joined us further down the road, not even very close.”5
Highlighting the turnaround, Professor Ulfur Arnason of Sweden’s Lund University, remarked that “the classic orders are not as self-evident as we previously thought”, adding, incredibly: “We are more closely related to flying lemurs than we are to half-apes.”7
In a remarkable use of spin, Dawkins refers positively to the changeability and uncertainty of ideas about evolutionary pathways, even using it in The Ancestor’s Tale as the ‘moral’ for his section entitled “The Colugo’s Tale”:
“The affinities of the tree shrews and the colugos, to each other and to the rest of the mammals, are subject to dispute and uncertainty. There is a lesson in that very fact, and it is the lesson of the Colugo’s Tale.”5
Dawkins was certainly right about “dispute and uncertainty”. Subsequent published research papers contradict each other in their interpretations of molecular and genomic data. While researchers agreed that the formerly “prevalent interpretation” that “bats and colugos are sister groups” had now been “resoundingly rejected by all molecular studies”, the uncertain placement of colugos relative to tree shrews and primates is very much “still a matter of debate”.2,8,9
As Dawkins admitted in “The Colugo’s Tale”:
“There is a correct tree of life, but we don’t yet know what it is.”5
The colugo’s characteristic ‘mix’ of features utterly foils evolutionists’ attempts to invent for it an evolutionary history (see box).
Fossils reflect stasis, not evolution
The fossils are no help to evolutionists, either. They concede that “the first true dermopteran fossil”, allegedly 34 million years old, “differs little from modern colugos”.10
Why has there been no evolution in all that (supposed) time?
Designed for treetops lifestyle
Evolutionists’ disparagement of the colugo as ‘primitive’ contradicts their own observations. E.g., the colugo is “the champion of all gliding mammals”.11 With its “superior gliding skills”,1 it can glide more than the length of a football field, execute 90-degree turns and then gently alight on a tree trunk. Gliding is certainly a great way to move from tree to tree in southeast Asia’s tropical forests where tree canopies are often discontinuous (i.e. not joining). It uses much less energy than climbing down then up, and avoids terrestrial predators. And such is the colugo’s aerodynamic efficiency that it loses only one metre of vertical height for every 12 or so metres travelled horizontally.
In a single night, a colugo might have to travel as far as 3 km (2 miles), to find its fill of young leaves (diet can also include flowers and fruit). The colugo masterfully controls its launch and landing—slowing its gliding speed by 60% and spreading the landing impact across all fours with its needle-sharp curved claws embedding securely into the tree trunk in one seamless land-and-hold-tight operation. This requires a whole lot more than the gliding membrane to be fully functional—everything had to ‘work’ from the very first!
What do colugos do if foliage gets in their way? One researcher recalls that “they will actually collapse their membrane, haul through the leaves and then open up and glide some more. Obstacles are not much of an issue for them.”11
Studying colugo flight, researchers say, could help improve the design of hang gliders and micro air vehicles.11 Its highly prized “long, soft, and luxurious” fur “appears to dampen turbulence”.12
Such evident design attributes point to the colugo having indeed been designed, by the Designer spoken of in the Bible. Around 6,000 years ago He created creatures to reproduce “according to their kind” (Genesis 1:24–25), perfectly consistent with the fact that fossils show that colugos have always been colugos. It’s no accident that the colugo’s design thwarts naturalistic explanations of origins (Romans 1:20).
The colugo is beautifully fit for real trees, not evolutionary ones.
Mix of colugo features stymies evolutionists
The colugo ‘mosaic’ of features—both unique and shared with other creatures—thwarts even the most creative evolutionary storyteller’s conceptions of what evolutionary pathways might have led to it:
- Colugos are placental mammals, but marsupial-like in their breeding habits. The young are born after only 60 days of gestation, still tiny (35 g = 1.2 oz; cf. adults weigh up to 1.75 kg = 3.85 lb) and undeveloped, i.e. early in embryonic development. They spend the first six months after birth clinging to their mother’s belly. Unlike marsupials, however, the mother has no pouch. To protect her young, she curls her tail up to fold the gliding membrane into a secure ‘makeshift’ pouch. When the mother hangs upside down, this patagium functions as a warm and furry ‘hammock’ for her tiny offspring (photo pp. 28-29). Of course, when mother is in gliding mode there is no such protection—imagine the dire consequences for the future of the species if the first baby colugos did not already have the wherewithal to cling on for dear life!
- Like bats (order Chiroptera), but unlike other gliding mammals, the neural spines (bony projections) of the colugo’s thoracic vertebrae (chest spinal region bones) are short, the sternum is slightly keeled, the space between the colugo’s fingers and toes is webbed, and the end of the ulna is “strongly reduced”.12 However, unlike bats (but like other gliding mammals), the colugo does not flap its ‘wings’, and has distinctly different anatomy.
- Colugos have a lemur-like face, with large eyes—hence (erroneously) “flying lemurs”.
- Colugos have highly unusual teeth. E.g., the first two lower incisors are unique among mammals in that the crown is notched and comb-like, with up to 20 tines on each tooth.
- Colugos have a small brain and large cerebral ventricle (a distinctive space in the brain) similar to the koala and tree sloth, and highly unusual ear region—distinctly different from primates. This and the lack of certain key features possessed by primates frustrates the contention that colugos are our “last common ancestor”. E.g., a swag of head and neck muscles present in both tree shrews and primates are absent in colugos.13
References and notes
- Tree-dwelling colugos glide between the trees, BBC Learning Zone Scotland—clips edited from BBC programmes, accessed at www.bbc.co.uk on 5 November 2010. Return to text.
- Martin, R.D., Colugos: obscure mammals glide into the evolutionary limelight, Journal of Biology 7:13, 2008. Return to text.
- Dawkins, R., Climbing Mount Improbable, W.W. Norton & Company, New York, 1996, p. 113. See review by Sarfati, J., Journal of Creation 12(1):29–34, 1998; creation.com/dawkins. Return to text.
- Pettigrew, J., Flying lemurs and other animals, Nature 346(6284):520, 1990. Return to text.
- Dawkins, R., The Ancestor’s Tale: A pilgrimage to the dawn of evolution, Houghton Mifflin Company, New York, USA, 2004. Quotes drawn from pp. 174–178. Return to text.
- As one evolutionist summed it up, “morphological interpretations, such as the placement of colugos with bats in the grouping Volitantia, frequently clash with the molecular evidence.” Ref. 2. Return to text.
- Flying lemur called another close relative of humans, UniSci—Daily University Science News, 20 June 2002. Return to text.
- Janecka, J., et al., Molecular and genomic data identify the closest living relative of primates, Science 318(5851):792–794, 2007. Return to text.
- Nie, W., et al., Flying lemurs—The ‘flying tree shrews’? Molecular cytogenetic evidence for a Scandentia-Dermoptera sister clade, BMC Biology 6:18, 2008. Return to text.
- Ducrocq, S., et al., First fossil flying lemur—a dermopteran from the Late Eocene of Thailand, Palaeontology 35(2):373–380, 1992. Return to text.
- Sanders, R., Tracking gliding behavior in the ‘flying’ lemur, University of California Berkeley Press Release, berkeley.edu/news/media/releases/2008/02/076_colugo.shtml, 7 February 2008. Return to text.
- Vaughan, T., Ryan, J., Czaplewski, N., Mammalogy, 5th edition, Jones & Bartlett Publishers, Sudbury, MA, USA, 2011—chapter 11: Dermoptera and Scandentia, pp. 162–166. Return to text.
- Diogo, R., The head and neck muscles of the Philippine colugo (Dermoptera: Cynocephalus volans), with a comparison to three-shrews, primates, and other mammals, Journal of Morphology 270(1):14–51, 2009. Return to text.