Unfalsifiable Hypotheses


Since March, I’ve been wandering around the Panamanian forest, watching birds and asking questions, hoping to come up with a few queries that are interesting and novel enough to be worthy of doctoral investigation.

The trouble with so many of my questions is that the hypotheses they generate are rather difficult to test. Wild animals–particularly volant vertebrates–come with certain observational and experimental limits. Additionally, due to a youth steeped in too much religion and literature, some of my hypotheses smack of just-so stories, ad hoc fallacies, and unfalsifiability.

Karl Popper. Photograph from Wikimedia Commons.

Sir Karl Popper. Photograph from Wikimedia Commons.

The philosopher Karl Popper is attributed with articulating and promulgating Science’s distaste for unfalsifiable hypotheses. In The Logic of Scientific Discovery, Karl Popper asserted that if a statement is to be scientific, it must be falsifiable: you must to be able to disprove it. If you can’t disprove it, than even most rational and coherent hypothesis can be considered a well-informed folkloric explanation.

In honor of all my reasonable, well-informed hypotheses that are tragically untestable–or at least, unreasonably difficult to test–I’d like to offer some unreasonable, ill-informed hypotheses as alternatives to standing theory.

1 – Lek Love

In many manakin species (Family: Pipridae), males form leks where they perform elaborate displays for passing females, with one or two males taking the vast majority of the mating success. Most studies on how these systems evolved and are maintained focus on males clustering around resources [1] or the more attractive males [2] to increase their access to females.

In my alternative hypothesis, male manakins do not form leks and dance for females. I believe that all male manakins are actually gay, and leks are their equivalents of dance clubs. They only copulate with the females to get them to leave.

Girl walks into a gay bar… clockwise from the top: Golden-crowned, Blue-capped, Lance-tailed, nondescript female, White-ruffed, and Red-capped Manakins

Straight girl walks into a gay bar… clockwise from the top: Golden-collared, Blue-crowned, Lance-tailed, nondescript female, White-ruffed, and Red-capped Manakins. Click on the links to see neat videos of each species’ courtship display.*

2 – Why Wag?

Motmots (Family: Motmotidae) are really nifty neotropical family of birds. When you approach a motmot, they’ll wag their pendulous tails from side-to-side like a feathered metronome, as in the video below. I find this behavior deeply charming, and I am tickled pink each time I catch a motmot tick-tocking its tail.

Current hypothesis holds that motmots wag their tails as a pursuit-deterrent against predators [3]. When a motmot twitches its tail, it is signaling its awareness to its hunter in an “I-see-you” of sorts. Its ambush foiled, the predator doesn’t waste its energy chasing the motmot, and the motmot wastes no energy being chased.

This explanation is grossly unsatisfying. I believe they wag their tails in an attempt to hypnotize unwary birdwatchers and implant suggestions for embarrassing social behaviors, triggered by alcohol. I’m certain this has happened to me twice since I arrived in Panamá, and is culpable for my untoward comportment at parties. Er-hem.

An inherently friendly Rufous Motmot (Baryphthengus martii).

An deceptively friendly Rufous Motmot (Baryphthengus martii), about to exert its mind control powers.

3 – The Cling of the Cocklebur

Cockleburs (Xanthium ssp.) are often cited as an example of animal-based (zoochorous) seed dispersal. Their tiny hooks grasp the fur and feathers to be taken way from their parent plants.

This is what the esteemed Justice Antonin Scalia** would call “a compendium of cockamamie“…or should we say cockle-mamie? Cockleburs do not hitch rides on your hiking shoes to disperse. Cockleburs are plagued by loneliness, and grab your socks just to feel close to someone.

Let them into your heart. Let them into your home. LET THEM IN.

Let them into your heart. Let them into your home.

4 – Aposematism Á La Mode

Perhaps more than any other ecotype, the tropics are chock-a-block full of poisonous nasties. From snakes to frogs to caterpillars , there are countless things that produce toxins which–if they don’t kill you–will at least severely discomfort you.

Heliconius butterflies may look like candy, but carry toxins from plants they ate in their youth. Image from Wikimedia Commons

Heliconius butterflies, with their candy coloration, are a great example of aposematic Müllerian mimicry. Image from Wikimedia Commons

Biologists have long noted that there many of these toxic creatures use similar patterns of bright, noticeable colors. It is hypothesized that these Müllerian mimics have come to share common “don’t mess with me” signals through convergent evolution. Additionally, some non-toxic species are deceptively similar to poisonous ones, and are thought to co-opt the signal through Batesian mimicry.

However, I argue that there is no such thing as Müllerian nor Batesian mimicry. All of these blaring colors are just ancient fads started by toxic individuals, and perpetuated by weaker individuals–much like fashion in humans.

This season's colors feature earth tones and neurotoxins

This season’s colors emphasize earth tones and neurotoxins


*Not all manakin species form tight leks. Some display by singly, or in spread-out, “exploded” leks.

**I cannot tell you (1) how overjoyed I was at the Supreme Court’s ruling on gay marriage last month, nor (2) how baffling I found Justice Scalia’s rebuttal. I mean, sure, Justice Kennedy’s opinion was a little too florid for my tastes, but Justice Scalia’s rancor seemed out of all proportion and propriety. Oh, well.


[1] TG Murphy. 2006. Predator-elicited visual signal: why the turquoise-browed motmot wag-displays its racketed tail. Behavioral Ecology 17(4): 547-553.

[2] R Durães, BA Loiselle, and JG Blake. 2007. Intersexual spatial relationships in a lekking species: blue-crowned manakins and female hot spots. Behavioral Ecology 18(6): 1029-1039.

[3] R Durães, BA Loiselle, and JG Blake. 2008. Spatial and temporal dynamics at manakin leks: reconciling lek traditionally with male turnover. Behavioral Ecology and Sociobiology 62(12): 1947-1957.


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