Travels of Pregnant Great White Sharks Revealed
by Douglas Main
For the first time, migrating great white sharks have been tagged and their movements around the oceans tracked for years, as opposed to the few months they have previously been tracked, according to a researcher.
Scientists used special satellite tags that tracked several sharks from a specific great white population for up to three years off the coast of Mexico. The study found that adult female sharks complete a two-year breeding cycle and avoid male sharks whenever possible, said study author Michael Domeier, a researcher and the president of the Marine Conservation Science Institute.
Published recently in the journal Animal Biotelemetry, the study followed four female great white sharks from their mating grounds off Mexico’s Guadalupe Island until they returned 24 months later, Domeier said. During the first 18 months, the females followed an ambling path through the open ocean, he said.
They then arrived in off Baja California to give birth to shark pups, putting themselves at risk of running into shipping traffic on their voyage along the shore, the study found.
“During the time the females are giving birth along the Baja Peninsula they are exposed to an array of commercial fishing activities that put them at risk,” Domeier told OurAmazingPlanet in an email. “Of course, the baby white sharks are at even more risk since they spend the first years of their life in coastal waters and their small size makes them even more susceptible to capture.”
Once the young sharks are born, the females return to Guadalupe Island to mate again.
The study found a high prevalence of bite marks on the sharks. Male sharks “bite the head, flank or pectoral fin of females during the mating ritual, but certainly these sharks are biting each other out of aggression as well,” Domeier added. “Males may be battling it out for access to females or preferred hunting grounds.”
While the females return to mate every two years, the males only return every other year. When they’re not mating, both males and females may range as far afield as the waters off Hawaii, Domeier said.
The researchers tag the great white sharks by affixing the device to the tip of the animal’s dorsal fin, during which time they are very close to the predators.
“It’s surreal and humbling,” Domeier said. “It is also stressful since the shark’s life is in our hands during the short time it takes us to capture and tag each individual.”
Source: Live Science
Photo Credit: Neil Hammerschlag
The Disposable Penises of a Nudibranch.
Little did I know, when I shot this critter, that it had a kinky talent of regeneration.
I say ‘it’, because nudibranchs are simultaneous hermaphrodites. During mating, the pair will impregnate each other. With the penis location on the right side, when the nudibranchs line up, they can inseminate themselves at the same time. The act takes anywhere from a few seconds, to a few minutes.
Post-coital observations (for Science) showed that as the nudibranches pushed away from each other, they ‘shed’ their penises.
In less than 24 hours, however, the nudibranchs had regenerated their penises and were able to mate again.
Apparently the reason for this being that a large amount of the penis is stored coiled up in a spiral inside their bodies, used to replace the missing part.
So what’s the advantage?
The researchers say that in the first act of copulation the penis may be used to remove any sperm left by any competitors that its partner has mated with.
With the first penis and the rival sperm then abandoned, the second penis can be used to inject the sea slug with another dose of its own sperm, ensuring that their genes are the ones that are passed on.
Photo: Samantha Craven
Journal Article: http://rsbl.royalsocietypublishing.org/content/9/2/20121150
Female Hawksbill turtles are monogamous.
Because “New insight into Hawksbill Turtles’ mating patterns” or “Hawksbill turtles’ monogamous sex life revealed” sounded creepy and overfamiliar.
Dr David S Richardson and Karl Phillips from the University of East Anglia looked at turtle nests on Cousine Island in the Seychelles, an eco-tourism holiday destination favoured by the rich and famous.
Working with the islands’ conservation staff they used a non-harmful procedure to collect DNA from the hard skin of the flipper, or around the shell.
The researchers looked at 43 mothers and 1600 young to reconstruct a genetic model of each nestling’s father, without having to catch the males out at sea. ‘It’s important to do this so that we can understand their mating system and see how much genetic variation there is within the population’ says Richardson.
This is the first comprehensive study into Hawksbill Turtle mating patterns and the findings may help conservationists refocus efforts to where they’re needed.
The scientists were surprised then to find all of the eggs from an individual female are normally fathered by the same male. This means the mothers mate only once and then store the sperm for the entire mating season, fertilising all their eggs with it.
Monogamy in the animal kingdom is the exception rather than the rule. Many females are forced to mate multiple times by aggressive males, or prefer to mate multiply to ensure they have the best quality sperm.
‘If they mate with one male and then met another one that was in some way better, bigger or stronger, they might re-mate and have a mix of eggs fertilised by both,’ Richardson explains. ‘However, it seems female Hawksbills would rather mate just once, far away from their nesting site, then store the sperm, perhaps to avoid unwanted male attention.’
Now the scientists know that not only are there lots of males fathering the nestlings, but there are many male turtles scattered far across the Indian Ocean. Conservationists can use this information to widen their efforts, from the beaches where the females lay their nests to the entire Indian Ocean area, in order to protect males too.
The bdelloid rotifer – a tiny, all-female creature – has endured the past 80 million years without sex. Now, researchers discover the asexual animal’s secret lies in gobbling up foreign DNA from other simple life-forms.
Meanwhile, the very first ejaculation “caught” in the fossil record some 400 million years ago tells the story of Earth’s sexual past.
First Ever Images of Deep Sea Squid Mating
This pair of mating Pholidoteuthis adami squid was observed by ROV Little Hercules on April 13 2012 at a depth of 1400 meters during an expedition by NOAA Ship Okeanos Explorer in the northern Gulf of Mexico. The male is upside down, and backwards on top of the female and the terminal organ ()presumably the white elongated structure) is extending from his funnel , presumably releasing spermatophores, from which spermatangia burrow into the dorsal mantle tissue of the female. The male has a firm grip on the female with at least three pairs of his arms…
(read more: Smithsonian)
(Image courtesy NOAA Okeanos Explorer Program)
Devoted Deep Sea Squid Mama
Parental instincts aren’t exactly common place in the invertebrate world. Squid typically die after spawning, leaving orphaned squidlets to fend for themselves in the big bad ocean. But as in all of biology, there are exceptions.
Check out this incredible image of a mama squid tending to her (approx. 360) eggs — only the second species of brooding squid to be discovered, ever!
Man, the deep sea is cool. Cephalopods are also cool.
This paper was just published. Imagine how many more cool squid are down there.
This, my darlings, is a new species of Penis-head fish, Phallostethus cuulong, described from the Mekong Delta in Vietnam.
It joins others in the Phallostethidae family - fish named for the placement of their copulatory organ. Termed the priapium, it is located under the throat for holding or clasping onto females and fertilising their eggs internally (as most penises do).
Researcher Tran Dac Dinh from Can Tho University in Vietnam uttered the words we all
secretly want to say “We have scientifically identified a new penis-head fish in [Vietnam]”.
Australian photographer Jason Edwards, who took the images off Tonga, was stunned by the “brief but tender” copulation.
While humpback “heat runs” - in which 15m-long, 40-tonne males fight to win a female’s attention - have been well documented, and often wrongly described as mating, this is the first time the actual act of copulation has been photographed, the National Geographic Channel said.
“It was amazing. There were four or five males vying for her attention and while the larger ones were busy jostling each other, the smallest one swam away with the female,” Mr Edwards said yesterday.
“Their coupling lasted less than 30 seconds, which might explain why it’s never been captured on film before.”
A truly beautiful underwater birth…
Is there anything cuter than a Flamboyant Cuttlefish that small?
If you think gestating one baby is tough, try 3,000. The squid Gonatus onyx carries around her brood of 2,000 to 3,000 eggs for up to nine months. The squid moms have their arms full: While carrying their eggs, they’re stuck swimming with their fins and mantle instead of their much more effective arms.
So why would G. onyx take such care of its thousands of offspring? According to a 2005 study published in the journal Nature, the squid carry their eggs to deep water, where predators are rare. The deep-sea offspring are also larger and more capable of survival than shallow water squid.
Do you think she has swollen tentacles too?