05 May 2014, 01:38 PM ET
During mating, the male sea turtle will reach his tail underneath the back end of the female's shell. His long penis, which can be almost half the length of his shell, will emerge from his cloaca to penetrate and inseminate the female's cloaca.
19 April 2014, 10:06 AM ET
Despite some human-like characteristics, elephants' mating behaviors are very different from our own.
17 April 2014, 11:42 AM ET
During copulation, lasting 40 to 70 hours, the female cave inserts her penislike gynosome into the male organ to collect sperm. The female's lengthy penis would be the equivalent of a 5 foot 9 man having a penis about 9.8 inches long.
17 April 2014, 11:15 AM ET
Females with penislike genitals and males with vaginalike organs are cases of a new extreme reversal of sex roles researchers have discovered in little-known cave insects.
09 April 2014, 03:11 AM ET
The reason why pandas are going extinct is nothing to do with their cycles. It is because so much of their natural environment has been destroyed.
02 March 2014, 08:41 AM ET
Tasmanian devil mating involves a lot of aggression, battles for dominance and infidelity.
08 February 2014, 09:13 AM ET
Dragonfly mating involves violent battles, flashy courtship dances and heart-shaped coitus.
02 January 2014, 06:07 PM ET
From small and subtle to large and in charge, sex in the animal kingdom is just as varied as the beasts themselves.
30 December 2013, 08:35 AM ET
Bat sex involves unique behaviors not seen in other mammals, including swarming, honking and oral sex.
03 December 2013, 09:13 PM ET
Peafowl sex is a sight to behold, involving brilliant train displays, rattles and hoot dashes. Once the peacock and peahen have mated, they go their separate ways.
23 November 2013, 09:41 AM ET
Though their serpentine locomotion might be off-putting to some, when roundworms do the deed, they're surprisingly graceful. A simple animal with only about 300 neurons, C. elegans is a common model organism in biology laboratories. But its reproductive s
22 November 2013, 10:09 AM ET
The mating behavior of the roundworm C. Elegans is surprisingly sophisticated, requiring complex nerve control.
12 November 2013, 07:02 PM ET
A simultaneous hermaphrodite, the slug has both male and female reproductive organs that it uses simultaneously during sex. The male organ is a two-pronged penis equipped with spines.
12 November 2013, 07:01 PM ET
Lots of animals take part in what humans might consider bizarre mating tactics, but one sea slug might take the cake: it stabs its partner in the head.
01 November 2013, 09:11 AM ET
Though they may look different, penguin mating behaviors are surprisingly similar to other birds. Even so, each of the 18 penguin species has its own little mating quirks, with some doing a look-see of the male's bachelor pad before shacking up.
15 October 2013, 11:42 AM ET
Sea lampreys use a digestive enzyme called a bile salt as a sexual pheromone, excreting it through their gills after not eating for weeks.
07 October 2013, 03:00 PM ET
Live fast, die young. Males of some insect-eating marsupials survive less than a year before mating until they die. They follow this strategy to increase the number of offspring they can sire, a study shows.
02 October 2013, 05:00 PM ET
For insects like aphids, a raindrop on their head is like a refrigerator falling on a human, so it behooves them to detect stormy weather and avoid such naughty acts.
02 October 2013, 08:47 AM ET
Unlike many other animals, kangaroos have sex for a long time — up to 50 minutes. And the female has three vaginas, two of which are inseminated by the male's double-headed penis.
27 August 2013, 09:40 AM ET
Seahorses have a sex role reversal, where males get pregnant instead of females. But how do they actually get busy and get pregnant in the first place?
23 August 2013, 01:11 PM ET
Females of two bug species may have figured out a way to lessen their chances of being on the receiving end of their species habit of "traumatic insemination."
15 August 2013, 04:52 PM ET
Homosexuality has been found in a wide range of animals, but it is not well understood in the insect world. A recent review of insect homosexuality shows that, for the most part, it occurs as a mistake.
25 July 2013, 09:27 PM ET
Sure, birds can fly, but how do they have sex? Can they do it in the air? And where do they keep their reproductive organs? For humans to understand bird sex, they must first put all thoughts of mammalian sex organs out of their heads.
24 July 2013, 11:04 AM ET
The Newport Aquarium in Kentucky announced the death of its latest acquisition, a shark ray. The exotic-looking fish — also known as a bowmouth guitarfish — was killed during the act of mating by an amorous male.
24 July 2013, 08:13 AM ET
Scientists have never documented blue whales mating, but they know there is a dating period where a male follows a female for weeks on end. And sex is not a forgone conclusion for the couple, it seems.
01 July 2013, 11:39 AM ET
This ugly parasitic fish generates heat when potential mates swim by.
26 June 2013, 07:05 PM ET
Females use one shot of sperm to fertilize their eggs for the rest of their lives.
17 June 2013, 05:20 PM ET
Tough love: After mating, male fishing spiders spontaneously die.
04 June 2013, 07:01 PM ET
Rather than fertilizing her eggs, the female squid scoops sperm up for a healthy snack.
30 May 2013, 07:42 AM ET
Most crabs prefer the missionary position while essentially "naked."
18 May 2013, 09:03 AM ET
It involves a peculiar male dance and multiple partners.
29 April 2013, 07:22 AM ET
Some male newts, sans any penises, use powerful pheromones to drive females wild.
17 April 2013, 08:02 AM ET
Are these fearsome predators gentle lovers?
08 April 2013, 02:34 PM ET
With all the interest in duck sex these days, a lecture by the discoverer of gay mallard necrophilia seems timely.
05 April 2013, 08:34 AM ET
Let's just say the risky business involves pedipalps covered in sperm juice.
01 April 2013, 11:48 AM ET
Bats show a surprising range of sexual behavior.