6 Animal Sex Lives (Manipulated by the Cold Hand of Science)

  • August 09, 2010
  • 187,505
  • Science
  • Image Sources

Side-Blotched Lizards

side blotched lizards01

The Species:

Side-blotched lizards have a pretty complex mating system. They live in the deserts of western North America and are extremely territorial, which is a tricky thing to be in the desert: there’s not much distinguishing a lousy sand dune from an awesome dune as far as we can tell.

side blotched lizards02

Some Dunes are easier to judge than others.

The males come in one of three different colors: orange, yellow and blue. The orange guys are the Vikings of their species: they control large territories and mack on lots of lady-lizards. The blue ones are the more sensitive, monogamous types: they can get beat down by the orange males, so they control small territories that can support one female. Finally, the yellow dudes are the weak sneakers: they hang out on the fringes of the orange territories and have sly sex when the males are away.

side blotched lizards03

The lizard equivalent of that jerk your girl is “just friends” with.

So what makes one territory better than another? Rocks. More rocks means more places to bask, hide and find bugs. Still, observing that males with the most rocks had the most mating opportunities wasn’t enough, apparently. Researchers would need to do some meddling to justify their grant requests.

The Makeover:

In order to really, super confirm that the ladies actually cared about the rock quantity instead of colors, researchers decided to mix things up a bit. After the lizards had established territories, scientists simply snuck in and dumped some of the big rocks from the dominant orange territories into the lower ranking blue territories.

Evidently, this was akin to giving the nerdy guy in school a sweet Ferrari. The mating success of the formerly lonesome lizards jumped significantly. The ladies didn’t totally abandon the large lizards though. In fact, genetic analysis of offspring indicated that many of the females were able to differently allot the sperm used to fertilize their eggs.

Sperm from the large males was used to produce male offspring. Sperm from smaller males was used to produce female offspring. Evidently, the good rocks were enough to get the wimpy lizards laid, but not enough to help them avoid the lizard equivalent of dance recitals.


Rock Sparrow

rock sparrow01

The Species:

The rock swallow is a pretty common bird, living in the Old World sweet spot from northern Africa to southern Europe, west to central Asia.

Like most species, come breeding season, rock sparrows pair off. Also like most species, the courtship of these frisky flyers takes the form of the males courting females for attention. However, in captivity, scientists noticed that the men seemed to be exerting a degree of selection themselves. The most “desirable” ladies were far more popular with gents. They spent more time pursuing and courting them, and these feathered hotties were found to breed earlier and more often, cranking out more chicks in the process.

What was it that so attracted the attentions of the males of the species? In a word, tits.

rock sparrow02

Just because you can’t tell the difference doesn’t mean they can’t.

The Makeover:

Not content with the casual observation that ladies with a bigger breast size were the VIPs of the mating grounds, researchers decided to get equally freaky. If the males are concerned mostly about the female breast size (i.e. the size of the yellow breast patch that we will refer to as “cleavage”) then doing a low budget breast reduction should be a turn off.

What they found is, well, exactly that. Females with larger cleavage are much more popular than those with simulated avian A-cups. Reducing the size of the breast patch resulted in a similar reduction of male interest: courtship dropped to 2/3 the normal rate and “sexual chases” dropped to half, meaning the voluptuously-challenged mated later and less frequently.

It should be noted: the scientists did not attempt to increase the size of the breast patches. Their reasoning was that previous research has shown that the positive response from males to sexual enhancements is much lower than the negative response to sexual reductions. So, essentially, there’s probably no need to reach for silicon just yet.


Swordtail Fish

swordtail fish01

The Species:

Swordtail is the name given to a few species of freshwater fish that live from Mexico to Central America. They've become a popular aquarium fish, thanks to our willingness to play God with their genetics and their most defining feature: the sword.

The males of the species have freakishly long lobes on their tails, close to half their body length, that resemble the medieval weapon of the same name. Just like in humans, the ladies judge the men by the size of their "lower appendage".

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Oh yeah he’s got a huuuuuuuuuuuuuuge bank account. Tiny junk, though.

Since nature doesn't provide the poor creatures with pants or even expensive cars to compensate, the less endowed males mate much less. In fact, a particularly girthy gentleman swordtail can be so massively impressive; it causes juvenile males to remain immature. That’s like you catching a peek of your dad naked in the shower and it causing puberty to be delayed for three years.

The Makeover:

Since it wasn't obvious enough what was going on, researchers decided to see if the sword makes the fish, or if the fish makes the sword. Several of the luckiest male fish ever had artificial swords attached to turn them into aquatic John Holmes'. It was found that adding some additional ‘blade’ turned former zeros into the big fish in the small pond.

swordtail fish03

Not the only species to try that kind of thing.

Interestingly enough, this desire for long, hard man-rods seems to be ingrained in the ladies on a deep, subconscious level. In further experiments, scientists added swords to a very closely related (but naturally sword-free) species. The ladies must not have known what they were missing, because it drove them wild, even though the males were normally sword eunuchs.

Apparently, science discovered what we've known for years: women just appreciate a large package.

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Have you got something to add? Conducting your own sexy research? Witnessed a scientist doing unspeakable things to a pair of mating antelope? Join the discussion in the comments below!

Written by Kevin Mack – Copyrighted © www.weirdworm.com Image Sources

Image sources:

  • - Bower Birds: http://blogs.sundaymercury.net/weirdscience/satin_bowerbird_courtship.jpg
  • http://luirig.altervista.org/cpm/albums/bot-hawaii29/14231-Solanum-seaforthianum.jpg http://greenville.metromix.com/content_image/full/1617250/560/370
  • - Guppies: http://resources.waza.org/files/images/w%28415%29h%28252%29c%281%29q%2890%29/b74ad03781105e5ab5c41913857f0d2a.jpg
  • http://cache.gawker.com/assets/resources/2008/03/mystery1.jpg http://www.yumyucky.com/.a/6a010536e3fd46970c01156f77d540970c-pi.jpg
  • - Widowbirds: http://farm1.static.flickr.com/176/374735624_d22b86fc2e_o.jpg
  • http://randomknowledge.files.wordpress.com/2007/09/250px-reichelt2_2.jpg http://www.trophyexotics.com/louisiana%20upland%20game%20bird%20hunt%20quail%20and%20chukar%20hunt%20avec%20moi%20charlie%20ledoux%20%28337%29515-hunt%20%284868%29.....JPG
  • - Side-Blotched Lizards: http://www.richard-seaman.com/Reptiles/Usa/California/CoachellaValley/SideBlotchedLizard.jpg
  • http://www.criticalgamers.com/archives/pictures/DuneBoardgame.jpg http://faculty.ucr.edu/~chappell/INW/herps/sideblotched2.jpg
  • - Rock Sparrow: http://www.limosaholidays.co.uk/tourpics/tour455_1.jpg
  • http://upload.wikimedia.org/wikipedia/commons/thumb/8/8d/Petronia_petronia.JPG/645px-Petronia_petronia.JPG
  • - Swordtail Fish: http://www.fishchannel.com/images/article-images/swordtail-500.jpg
  • http://cdn.hellobeautiful.com/files/2009/02/1335293-1.jpg http://image52.webshots.com/152/4/3/25/2341403250084650083XrnYgq_ph.jpg