Getty Images

Neanderthals like the one depicted in this museum reconstruction died out tens of thousands of years ago.

By Jennifer Viegas
Discover News

The skeletal remains of an individual living in northern Italy 40,000-30,000 years ago are believed to be that of a human/Neanderthal hybrid, according to a paper in PLoS ONE.

If further analysis proves the theory correct, the remains belonged to the first known such hybrid, providing direct evidence that humans and Neanderthals interbred. Prior genetic research determined the DNA of people with European and Asian ancestry is 1 to 4 percent Neanderthal.

The present study focuses on the individual’s jaw, which was unearthed at a rock-shelter called Riparo di Mezzena in the Monti Lessini region of Italy. Both Neanderthals and modern humans inhabited Europe at the time.

PHOTOS: Faces of Our Ancestors

“From the morphology of the lower jaw, the face of the Mezzena individual would have looked somehow intermediate between classic Neanderthals, who had a rather receding lower jaw (no chin), and the modern humans, who present a projecting lower jaw with a strongly developed chin,” co-author Silvana Condemi, an anthropologist, told Discovery News.

Condemi is the CNRS research director at the University of Ai-Marseille. She and her colleagues studied the remains via DNA analysis and 3-D imaging. They then compared those results with the same features from Homo sapiens.

The genetic analysis shows that the individual’s mitochondrial DNA is Neanderthal. Since this DNA is transmitted from a mother to her child, the researchers conclude that it was a “female Neanderthal who mated with male Homo sapiens.”

NEWS: Neanderthals Lacked Social Skills

By the time modern humans arrived in the area, the Neanderthals had already established their own culture, Mousterian, which lasted some 200,000 years. Numerous flint tools, such as axes and spear points, have been associated with the Mousterian. The artifacts are typically found in rock shelters, such as the Riparo di Mezzena, and caves throughout Europe.

The researchers found that, although the hybridization between the two hominid species likely took place, the Neanderthals continued to uphold their own cultural traditions.

That's an intriguing clue, because it suggests that the two populations did not simply meet, mate and merge into a single group.

NEWS: Neanderthals Died Out Earlier Than Thought 

As Condemi and her colleagues wrote, the mandible supports the theory of "a slow process of replacement of Neanderthals by the invading modern human populations, as well as additional evidence of the upholding of the Neanderthals' cultural identity.”

Prior fossil finds indicate that modern humans were living in a southern Italy cave as early as 45,000 years ago. Modern humans and Neanderthals therefore lived in roughly the same regions for thousands of years, but the new human arrivals, from the Neanderthal perspective, might not have been welcome, and for good reason. The research team hints that the modern humans may have raped female Neanderthals, bringing to mind modern cases of "ethnic cleansing."

Ian Tattersall is one of the world’s leading experts on Neanderthals and the human fossil record. He is a paleoanthropologist and a curator emeritus at the American Museum of Natural History.

Tattersall told Discovery News that the hypothesis, presented in the new paper, “is very intriguing and one that invites more research.”

Neanderthal culture and purebred Neanderthals all died out 35,000-30,000 years ago.

Franky Bossuyt

The male alpine Ichthyosaura alpestris newt knows that it isn't the tail waving that attracts the ladies, but the pheromones that he uses.

By Joseph Castro
LiveScience

It may be time to crown male newts as the female-arousing kings — the amphibians release powerful pheromones that put females in the mood to mate with practically any adult around, even other females from different newt species, new research shows.

"The females react as if they're under the influence of drugs," said lead researcher Franky Bossuyt, a biologist at Vrije Universiteit Brussel (Free University of Brussels) in Belgium. "We were convinced that if we put in a plastic toy moving at the right speed, they would follow it."

Newts typically live on land as adults and mate exclusively in water. During the breeding season, males adopt intense color patterns and grow skin extensions on their legs, tail and crest. These changes are thought to make males more attractive to females.

When two newts meet, the male releases pheromones and waves his tail, sending the chemical signals to the female. They then play out a mating dance akin to a short game of tag, with the female following after the male. To let him know she's ready to get down to business, the female touches the male's tail with her nose, prompting him to deposit his spermatophore — a jellylike mass containing sperm— onto a substrate in the water, such as a leaf. Finally, he leads the female over the sperm packet, which sticks to her cloaca (the orifice leading to intestinal, reproductive and urinary tracts), resulting in insemination.

For years, scientists thought males waved their tails to disperse "attractant pheromones," which broadcast the male's presence and bring newt pairs together. But there's a problem with this idea: The newts have already introduced themselves before the male waves his tail. "The females are not attracted to the males by the tail-waving, at least with the newts I've seen," Bossuyt said.

Instead, the researchers thought, the tail fanning might disperse "courtship pheromones" that alter the female's behavior to stimulate mating.

Newt mating game
To find out, researchers placed male-female pairs of alpine newts (Ichthyosaura alpestris) and palmate newts (Lissotriton helveticus) into water-filled plastic containers for receptivity tests. The newts passed the test and were ready for the next phase if they completed the courtship ritual (females weren't allowed to complete the insemination).

The team then put two-female pairs into pheromone-infused courtship water; some pairs consisted of two alpine newts, other pairs had one female of each species. If the water contained pheromones from a male of her species, the female would desperately try to court the other female. In some cases, two female alpine newts tried to follow each other, resulting in the pair circling one another. In some two-species trials, one female chased after another, even as the unreceptive partner tried to escape the container. [See video of the sex-crazed newts]

But the amphibians didn't remain patient forever. Not receiving the spermatophore she expected, the courting female eventually started waving her tail at her partner, possibly sending out pheromones.

Frustrated females
"Female tale-waving is a kind of frustration behavior," Bossuyt explained, adding that females also tail-waved in receptivity tests to get males to continue courtship after researchers removed the spermatophores. In natural settings, this behavior probably happens only in uncommon situations, such as when a male is too tired for courtship. "So female tail-waving likely happens in nature, but you will not easily observe it," he said.

The results suggest the pheromones don't just announce the male's arrival, given how they induced such an overpowering mating reaction in the females. The researchers think males may have evolved such potent pheromones out of necessity, since newts often breed in turbid water with other newt species, making it difficult to mate based on vision alone.

It seems a male newt's flashy appearance matters little to females: It's all about his smell.

The research was detailed online this month in the journal PLOS ONE.

Follow LiveScience on Twitter @livescience. We're also on Facebook and Google+.

• Mug Shots: 10 Lost Amphibians
• Slithery, Slimy: Images of Legless Amphibians
• 10 Amazing Things You Didn't Know about Animals

Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Kazuki Kimura

An Euhadra quaesita snail, which, like other snail species, uses a "love dart" to stab its partner while mating.

By Rachel Kaufman
LiveScience

When snails decide to get it on, they don't turn on Barry White to get in the mood. Nor do they give each other chocolates or roses. Instead, during snail foreplay, one partner stabs the other with a so-called "love dart," a sharp dart produced by the snail's body to aid copulation. Talk about romantic.

About a third of all snail species manufacture these darts that are either calcareous (made of calcium carbonate, essentially chalk) or chitinous (made of or chitin, the stuff of insect exoskeletons). The snails literally stab these darts into their partners sometime during the (often) long, drawn-out mating process. But why employ this … unique … mating strategy?

Some studies have found that these darts help a snail's sperm survive longer inside its partner. The darts deliver a healthy dose of mucus and hormones that help the sperm reach a storage area within the female reproductive system by closing off "dead-end" pathways.

Now, new research has found that something in the love dart has a second function: It makes Euhadra quaesita snails slower to re-mate. [10 Amazing Things You Didn't Know About Animals]

Kazuki Kimura, a researcher in the department of ecology and evolution at Tohoku University in Sendai, Japan, and colleagues studied 50 E. quaesita snails, a common large land snail in eastern Japan. The researchers paired snails up and gave them the opportunity to get physical every two days.

The results were clear: "When snails were stabbed with the love-dart, they re-mated after the next 15 days," Kimura told OurAmazingPlanet. "When snails were not stabbed, the intervals were about 7 days."

Perhaps the ladies were actually just reluctant to get stabbed a second time? (Actually, snails are hermaphrodites, and both partners do plenty of stabbing during their 2- to-2.5-hour mating sessions.) To test whether the snails were physically harmed during mating, Kimura and colleagues injected the mollusks with snail mucus. Simply having the hormones in their bodies made the snails much less likely to mate, so the simple physical effects of stabbing weren't to blame.

Finally, the snails — whether stabbed or injected — continued to lay eggs as normal, Kimura said. "So we think that sperm donors are expected to attain high fertilization success" while the mucus keeps the sperm recipient from re-mating, making the sperm donor more likely to father baby snails and have its genes passed on.

Next up: identifying what hormone in the mucus makes snails react this way. "I think this is fundamental knowledge to understand the evolution of love-dart mucus," Kimura said.

The study appeared online Jan. 21 in the journal Animal Behaviour and will appear in a forthcoming print edition.

Follow OurAmazingPlanet on Twitter @OAPlanet. We're also on Facebook and Google+.

• Top 10 Swingers of the Animal Kingdom
• Not Your Average Valentine: Roaches, Pandas and Ladybugs
• Gay Animals: Alternate Lifestyles in the Wild

Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.