How Bambi Gave Rise to Moby Dick

The title of this entry, in Kipling Just-So Story format, is only slightly modified from an article from The Guardian, titled, “How Bambi evolved into Moby-Dick.”  This is not a joke; check on the link and see.
    The article is about the latest fossil claimed to be ancestral to whales.  Hans Thewissen (Northeastern Ohio College of Medicine) has spent many years trying to trace an evolutionary path to whales from artiodactyls (even-toed ungulates, a group of mammals including deer, cattle, sheep, goats, giraffes, pigs, and camels).  This was the subject of a chapter in the PBS Evolution series, “Great Transformations,” in 2001 (see review on ReviewEvolution.com).  Thewissen’s latest candidate missing link is a raccoon-size deer-like fossil animal found in Kashmir; the discovery and analysis was published in Nature.¹  The Guardian was ebullient in its certainty that this is the link:

The landmark finding represents a long-sought ‘missing link’ in the 10m-year [10 million year] journey that saw ancient land mammals evolve into modern cetaceans, a group that includes whales, dolphins and porpoises.”
    Scientists have long known that whales are mammals whose ancient ancestors walked on land, but only in the past 15 years have they unearthed fossils that shed light on the creatures’ dramatic evolutionary history.  The latest discovery, named Indohyus, is the first whale ancestor known to have lived on land.

On what basis did Thewissen and his team think this fossil had anything to do with whales?  The teeth are “similar to those of aquatic animals,” and the bones suggest a heavy stance like that of hippos.  The bones around the inner ear look similar to those of cetaceans, the article claims.  That’s about all the data this article mentioned, yet the certainty that this represents the missing link continued:

The evolutionary path of the whale is one of the most extraordinary on record.  In less than 10m years, the whale’s ancestors completely transformed as they shifted from a four-legged life on land to a life in the ocean.
    The first whales, Pakicetidae, emerged around 50m years ago and resembled land mammals rather than the giant marine creatures of today.  These evolved into large, powerful coastal whales, or Ambulocetidae, that had big feet and strong tails.  Later, whales lost their hind limbs and hair and developed powerful tail fins and flippers.

One difficulty is that this fossil “overturns a previous assumption that the ancestors of whales were already carnivores before they left land for a life beneath the waves.”  Being a herbivore, what was it doing in the water?  Thewissen thinks it was acting like the modern mouse deer of Africa, which escapes from eagles by diving under the water for up to four minutes.
    To reinforce the missing-link message of Indohyus, the article stuck it to the creationists:

Fred Spoor, an anthropologist at University College London, said the significance of the latest find was comparable to Archaeopteryx, the first fossils to show a clear transition between dinosaurs and birds.  “For years cetaceans were used by creationists to support their views because for a long time the most primitive whales known had bodies that looked like modern whales, so there seemed to be this enormous gap in evolution.  But since the early 1990s, there’s been a rapid succession of fossils from India and Pakistan that beautifully fill that gap,” he said.
    “The tables are turned now because we have fossils that show that dramatic transition step by step.  Cetaceans are almost the only group that has made such a rapid change from a land environment to an aquatic one.  “Unlike sealions and seals, which still spend some time on land, cetaceans are completely committed to the water now, and it had an enormous effect on their physiology.  They had to change everything.”

This last sentence, they had to change everything, makes it sound as if the whales directed their mutations with the goal of becoming aquatic – that is most certainly not what the evolutionists mean.  Such language, however, blurs the way the Darwinian mechanism is supposed to work.  Individual members of Indohyus or cetaceans could not possibly know or care what was happening to them.  Evolution works on the genes in large populations over a long, drawn-out process involving mutations selection pressures without any goal in mind – certainly not in the minds of any individual animals.  No amount of individual striving gets passed on to the offspring – that would be Lamarckism.
    The article ends with the “more work to do” theme, but includes more purpose-driven language on the part of the whales:

Thewissen’s group will next study Indohyus further to learn more about its diet and habitat.  One critical change that occurred when whales took to the water involved its sense of balance and orientation.  In land mammals, this is governed by a vestibulary system in the inner ear, but whales had to adapt to moving in three dimensions, driving the evolution of a more complex system.
    “This fossil completes the picture in terms of the whales’ evolution, but what’s next is to look at these other evolutionary adaptations,” said Thewissen.

So the frame of the puzzle is done, and now it’s just a matter of filling in the middle.  Is that what the original paper said?  In the journals, scientists tend to be more reserved in their announcements than in the popular press.  It’s interesting that for a discovery this “dramatic” there was no review article accompanying the paper.
    The abstract says that Indohyus was a “sister group” to the whales.  This means it was not on the path to whalehood, but both had a common ancestor.  Claims that whale evolution is “documented” and “strongly supported” continue in the paper, but the opening paragraph leads one to suspect that a single fossil species like Indohyus cannot be expected to solve all the problems:

Phylogenetic analyses of molecular data on extant animals strongly support the notion that hippopotamids are the closest relatives of cetaceans (whales, dolphins and porpoises).  In spite of this, it is unlikely that the two groups are closely related when extant and extinct artiodactyls are analysed, for the simple reason that cetaceans originated about 50 million years (Myr) ago in south Asia, whereas the family Hippopotamidae is only 15 Myr old, and the first hippopotamids to be recorded in Asia are only 6 Myr old.  However, analyses of fossil clades have not resolved the issue of cetacean relations.  Proposed sister groups ranged from the entire artiodactyl order, to the extinct early ungulates mesonychians, to an anthracotheroid clade (which included hippopotamids), to weakly supporting hippopotamids (to the exclusion of anthracotheres.

Indohyus is an Eocene artiodactyl in a group Raoellidae, which previously had no linkage to the whale line.  Thewissen et al are therefore making a radical new hypothesis.  “This has profound implications for the character transformations near the origin of cetaceans and the cladistic definition of Cetacea, and identifies the habitat in which whales originated,” they say.  “Taken together, our findings lead us to propose a new hypothesis for the origin of whales.”
    New hypotheses, however, tend to create as many problems as they solve, because old assumptions get discarded.  Evolutionists have already been claiming for years that the whale evolution story is strongly supported with other fossils.  How can a specimen from a small, extinct deer-like animal wedge its way into an existing story?  It becomes necessary to juggle things around:

To investigate the importance of raoellids in cetacean phylogeny, we excluded raoellids from our initial phylogenetic analysis of artiodactyls plus cetaceans.  Our data set differed from previous analyses by the addition of several archaic anthracotheres, and some corrected scores for pakicetid cetaceans.  This analysis found stronger support for hippopotamid�cetacean sister-group relations than the previous analysis, consistent with molecular studies.  However, the base of the artiodactyl cladogram is poorly resolved (see Supplementary Information for details on phylogenetic runs).

This is how phylogenetic analysis is really done.  Assumptions are made, and some earlier associations get tossed by the wayside in an effort to achieve a desired amount of “consistency.”  So Thewissen and team changed the recipe and got some new flavors:

In a second cladistic analysis (Fig. 2), we added the raoellids Khirtharia and Indohyus as well as several archaic ungulate groups (condylarths) and found that raoellids and cetaceans are sister groups and that they are the basal node in the Cetacea/Artiodactyla clade, consistent with some previous analyses that used different character sets.  Our analysis is the first to show that raoellids are the sister group to cetaceans, resolving the biogeographic conundrum and closing the temporal gap between cetaceans and their sister.  Relations between most artiodactyl families higher in the tree are poorly resolved, and our data lack implications for the relations between these families.  Our analysis strongly argues that raoellids and cetaceans are more closely related to each other than either is to hippopotamids.

This is a human line of argument – not a single, clear, uncontroversial picture emerging inescapably from the data.  Everything is inference: trying to find a pathway through scattered data points, after first assuming a pathway exists.  The reader should not picture a straight line from Indohyus to Blue Whale.  The human researchers are picking their way through a data forest with a goal in mind.  The forest is not leading them on a single yellow brick road.
    Indohyus, for instance, has a thickening around its middle ear that was thought diagnostic of cetaceans.  What does this mean?  The paper presents two possibilities: either Indohyus was similar to whales, or this trait can no longer be thought characteristic of whales.  As with Tiktaalik, the data present mosaics of traits that require human judgment about what goes with what clade, and which clades are closer or farther apart.
    In the paper, the team considered various groupings, but made decisions based on their own preferences: e.g., regarding one alternative tree, they said, “We do not prefer this classification because it causes instability by significantly altering the traditional content of both Artiodactyla and Cetacea.”  The team sought the most “parsimonious” tree of descent – but parsimony is a human value, not a whale value.  Not even all humans will agree what constitutes parsimony.
    The team acknowledged that cetaceans and raoellids possess some synapomorphies (derived traits shared by terminal groups), but then said, “None of these features characterize all modern and extinct cetaceans; the dental characters, for instance, cannot be scored in toothless mysticetes.  In addition, all of these characters are found in some mammals unrelated to cetaceans.”  There are multiple ways to interpret the data, therefore.  The synapomorphies might indicate relationship – or, they could overthrow assumptions about which traits are diagnostic of which clades.  Clearly, this team did not attach any significance to the similarities that didn’t fit a deer-to-whale lineage.  “We attach particular importance to two character complexes that characterize basal cetaceans,” they said, but that assumes what needs to be proved (circular reasoning).
    The team attached great importance to the teeth.  But Indohyus, they said, was a herbivore, and whales are carnivores; how much about relationship can be inferred from teeth of groups with very different dietary habits and behaviors?  What kind of tree would have resulted had they attached particular importance to other traits?  One can imagine other evolutionary paleontologists having their own assumptions, preferences, methodologies, and arriving at very different conclusions. 
    Other traits were mentioned that do not help the story of whale evolution.  The team noticed that the leg bones showed osteoporosis, which they interpreted as meaning that Indohyus was stable in the water – but not a swimmer: “We interpret the limb osteosclerosis of Indohyus to be related to bottom walking and not to slow swimming, because the limbs are gracile and not modified into paddles.”  Other mammals, however, like beaver and otters and sea lions, show more modifications for aquatic lifestyle than this creature, and no one lumps them into a whale phylogeny.  So even if the oxygen or carbon isotopic ratios in the tooth enamel show a probability the creature lived a good part of its time in the water, how much can this tell us about its evolutionary path?  As a matter of fact, the team decided the diet of Indohyus was significantly different than whale diet.
    So here is the long and short about this creature:

Indohyus was a small, stocky artiodactyl, roughly the size of the raccoon Procyon lotor (Fig. 5).  It was not an adept swimmer; instead it waded in shallow water, with its heavy bones providing ballast to keep its feet anchored.  Indohyus may have fed on land, although a specialized aquatic diet is also possible.

Whales do not use their bones as ballast to stay anchored to the bottom.  They do not eat vegetables.  They do not walk on four feet.  By what kind of convoluted reasoning can a raccoon-size deer be considered ancestral to dolphins and blue whales?
    Even if it spent more time in water than the modern mouse deer, many mammals are accustomed to water: moose, bears, water buffalo, and of course otter and beaver – why are they not in the race to become whale ancestor?  The researchers even admitted that “The great evolutionary change that occurred at the origin of cetaceans is thus not the adoption of an aquatic lifestyle.”  They pinned all their inference on diet: “Here we propose that dietary change was the event that defined cetacean origins,” they said – but that is a radically new proposal from what they said before, because Indohyus eats plants, and whales don’t.  By all measures, it seems this new creature is even further removed from whale ancestry than the last candidate.
    Their ending paragraph summarized the just-so story of how Bambi evolved into Moby Dick:

Our working hypothesis for the origin of whales is that raoellid ancestors, although herbivores or omnivores on land, took to fresh water in times of danger.  Aquatic habits were increased in Indohyus (as suggested by osteosclerosis and oxygen isotopes), although it did not necessarily have an aquatic diet (as suggested by carbon isotopes).  Cetaceans originated from an Indohyus-like ancestor and switched to a diet of aquatic prey.  Significant changes in the morphology of the teeth, the oral skeleton and the sense organs made cetaceans different from their ancestors and unique among mammals.

This is, as they themselves said, only a “working hypothesis” at best.  Compare that with the triumphal announcements in the The Register quoted at the beginning of this entry: “The tables are turned now [against the creationists] because we have fossils that show that dramatic transition step by step.”
Update 12/26/2007: Science Now reported on the Thewissen claim, but ended with an alternative: “Another analysis, in press at Cladistics, suggests that an extinct group of carnivorous mammals, called mesonychids, were more closely related to cetaceans.”  Mesonychids looked less like Bambi and more like the Big Bad Wolf.  The only similarity seems to be that they were equidistant from Moby Dick.

1.  Thewissen, Cooper, Clementz, Bajpai and Tiwari, “Whales originated from aquatic artiodactyls in the Eocene epoch of India,” Nature 450, 1190-1194 (20 December 2007) | doi:10.1038/nature06343.

Will evolutionists actually tell lies to push their beliefs?  Yes—you saw it right here.  Fred Spoor told you that Archaeopteryx represents a clear transition between dinosaurs and birds, when he knows full well it appeared too late in his own evolutionary timeline to be a missing link (10/24/2005).  The big lie in the Nature article, and in the popular press, was to portray this fossil discovery as a great victory for evolution, and a step-by-step sequence showing the whole ancestry.  It is no more victory than picking up a spent lottery ticket on the dusty ground and thinking it is a missing link to riches.
    Philosophers of science could have some good banter about the logic of discovery – whether they discovered something true to nature in the data, or imposed their own experiences and preferences on the data.  Clearly, this team decided to pick and choose a few traits from a fossil they preferred over other problematical ones, and from these to weave a whale of a just-so story with which to dupe the public and shoot the creationists.  Well, their shot only hurt as much as a blast of bad breath in the face, that’s all.  You know what to expect from National Geographic, and you got it: “Whales Evolved from Tiny Deerlike Mammals, Study Says.”  The bigger the whopper, the better; have it your way, NG (10/24/2004).  Not to be left behind in the Whopper Olympics, the BBC News trumpeted, “Whale ‘missing link’ discovered.”
    This is the mess of things that Charlie Darwin left in his wake when he allowed the magicians and storytellers into the once noble halls of science (12/22/2003 commentary).  It’s time to clear house and clean up.  Send the whole lot of them back to school to learn some history and philosophy and ethics, and make them sign a commitment to speak the truth, the whole truth and nothing but the truth.  That would solve most of the problems in the contentious creation-evolution debate.
    Bambi to Moby Dick—incredible.  PhD scientists actually believe that?  They want that taught in the schools?  We need a new word that means to laugh and cry at the same time, because this whale of a tale deserves a whopping blubberfest.  Maybe the word howl will do.  Perhaps this is why the humpback whales are howling.