Swallow the young for them to grow?

Figure 1: A tiny froglet emerging from its mother's mouth

Figure 1: A tiny froglet emerging from its mother's mouth

Isn’t amazing to see a froglet coming out of a tiny mama frogs’ mouth? It intrigued me to find out more about this mini frog. It has the common names known as “Gastric brooding frog” or “Platypus frogs” which were a genus of ground-dwelling frogs native to Australia. This genus was unique as it consisted of only two species, Southern Gastric brooding Frog (Rheobatrachus silus) and Northern Gastric brooding Frog (Rheobatrachus vitellinus), that breed the young frogs in the stomach of the mother and give birth through mouth.

From the photo, you can see how small the mother frog is compared to human finger. Hence, why do they have such a unique reproductive method?  Before Gastric brooding females swallow the fertilized eggs, females give up eating and drinking for those six weeks so as to reserve the stomach merely for the tadpoles. The developments of tadpoles take place in female’s stomach. Initially, scientists were puzzled by how the females manage to “switch off” the secretion of digestive fluids (hydrochloric acid) during brooding. From the research, they found out that the tadpoles produce hormones which cause the female to cease the production of digestive fluids. It protects them from being digested in the stomach of the mother.

The development manner of tadpoles in the stomach is same as the aquatic tadpoles of other species as they all feed off egg yolk, the labial teeth are absent and the intestines form at a later stage of development. However, where do the tadpoles in the stomach get the egg yolk? The eggs are significantly larger than the eggs of the other species which contain a yolk rich in proteins, adequate to feed the tadpoles for the entire period of development. Hence, after 6-7 weeks the females can give birth to up to 25 young, birth is done by the female widely opening her mouth and dilating her gullet (esophagus). The froglets are propelled from the stomach to the mouth, and then jump away, at intervals over a period of several days (Tyler and Carter, 1981).

The unique reproduction of Gastric Brooding Frogs which is also known as exclusive form of parental care makes them to be so special among vertebrates. However, this species is currently listed as Extinct by the International Union for the Conservation of Nature. No individuals have been observed in the wild since 1981, despite extensive searches. It is a sad thing to know about it.



“Rheobatrachus silus — Southern Gastric Brooding Frog with baby in its mouth,” by D. Sarille. Save The Frogs, 20 April 2008. URL: http://www.savethefrogs.com/gallery/v/Extinct_Amphibians/Rheobatrachus_silus_with_baby.html (accessed on 5 April 2010).


“Rheobatrachus silus,” by Semeyn, E. 2002.Hosted on Animal Diversity Web: http://animaldiversity.ummz.umich.edu/site/accounts/information/Rheobatrachus_silus.html (accessed on 6 April 2010).


“Gastric Brooding Frog,” URL: http://www.global-greenhouse-warming.com/gastric-brooding-frog.html (accessed on 5 April 2010).


Tyler, M.J. & D.B. Carter, 1981. Oral birth of the young of the gastric-brooding frog Rheobatrachus silus. Animal Behaviour, 29(1):280-282.

Corben, C. J., Ingram, G.J., & Tyler, M.J., 6 Dec1974. Gastric Brooding: Unique Form of Parental Care in an Australian Frog. Science, New Series, 186(4167): 946-947

Cleaners in the waters?

Have you ever wondered how fishes keep themselves clean?

Or do they even need to be cleaned?

Well, small animals called the cleaner shrimps, such as the Periclimenes longicarpus, as shown in the picture below, cleans the fishes! The shrimps will be hanging around the cleaning stations in the waters and when a fish stops by, the shrimps will climb onto the fish. They will then use their claws to pick off detritus, dead skins, ectoparasites and tiny pieces of food. If the mouth of the fish is open, the shrimp will also climb into its mouth to clean.

Periclimenes longicarpus

These cleaner shrimps are actually much more than we can imagine – they clap to indicate their hunger levels. This means that when these cleaner shrimps are hungry, they will clap their claws! The rate of signaling in the shrimps will increase when they are deprived of food, that is, the demand for cleaning is low. Signaling by the shrimps can also be seen as a form of advertisement of service, so that the exchange of commodities ( the cleaner shrimps get food while the fishes get cleaned up) with clients – the fishes, will be better. Moreover, clapping may serve as both visual and auditory or vibration identity signals (Hasson 1997) as many reef fishes have low resolution power (Marshall 2000). Hence this will enable the fishes to locate the cleaner shrimps.

These cleaner shrimps are brave too!

In the marine cleaning interaction, the symbiotic relationship formed between the shrimp and the fish is of great trust. This is because some of these fishes that stop by at the cleaning stations can be predatory fishes which can just prey on the cleaner shrimps easily when they are cleaning them.

So fishes in the marine environment do actually “bathe” as well! Their bodies are being clean by “cleaners” in the waters such as the cleaner shrimps. To end this post, follow the link and enjoy this youtube video about the cleaning symbiosis among Hawaiian reef fishes, moray eels, sea turtles and cleaner shrimps. It illustrates that not only fishes get cleaned but other marine animals as well, even humans!

Cleaners in the Marine Environment




Hasson, O. 1997. Towards a general theory of biological signaling. Journal of Theoretical Biology, 185, 139–156.

 Lucille Chapuis, Redouan Bshary, Signalling by the cleaner shrimp Periclimenes longicarpus. Animal Behaviour, Volume 79, Issue 3, March 2010, Pages 645-647

 Marshall, N. J. 2000. Communication and camouflage with the same ‘bright’ colours in reef fishes. Philosophical Transactions of the Royal Society B, 355, 1243–1248.


“Odd Couples” by Amy Sarver. National Geographic Explorer. Pages 6-11, January-February 2006 issue. URL: http://magma.nationalgeographic.com/ngexplorer/0601/articles/mainarticle.html (accessed on 3 April 2010)

“Photos get the flavour of scienceby Jonathan Amos. BBC News, 28 September 2005. URL: http://news.bbc.co.uk/2/hi/science/nature/4291912.stm (accessed on 3 April 2010)

 Photographs/ Video

 “El Gouna 02.2009 422” by Alain76. Alain76’s photostream: El Gouna, Egypte 2009 (Set). URL: http://www.flickr.com/photos/12163936@N03/3268716503/ (accessed on 3 April 2010)

 “Hawaiian Showers – Cleaning Stations in Hawaii + Scuba Diving” by LivingOceanProd, Youtube Channel, 17 March 2008. URL: http://www.youtube.com/watch?v=OMFiI2at1p4&feature=related (accessed on 3 April 2010) 

Why arrows? Strike with love darts!

Why let the cupids decide? Learn from the helicid land snails ( for e.g. Helix Aspersa) and do it yourself!

 Most of us know that snails are hermaphrodites, meaning they have both male and female sexual organs, and they do not self-fertilize. But do you know that their genitals are on the necks, right behind their eye-stalks?

 Not interesting enough?

 They are the cupids themselves! But instead of arrows, the “male” (male sexual organs at work) shoots mucus-covered calcium “love darts” during the final stages of courtship to its partner preceding copulation!

Initially, it was thought that the “love darts” were gifts of nutrients, just like how we give presents to the person we fancy. However, further research has shown that there is more to it!

dart with mucus

“Love darts” are actually filled with sperm. When it is being shot to the partner, it penetrates into the body of the recipient and may get digested. However, the mucus outside paralyses the partner’s reproductive tract, allowing the sperm to avoid digestion and thus greater number of sperms can make it to the sperm storage sacs within the reproductive system (Pomiankowski et al. 2001). Good news, as the stored sperms may be enough to be used over a period of months or even years! Say YAY to more offspring!

So, why is there a need for “love dart” when snails can just simply copulate? Sadly, the chance of survival of sperm through copulation is extremely low, like only thousands in millions. Thus with “love dart”, it provides the edge over reproduction because more sperm will be available: Applying Darwin’s theory of sexual selection, snails want to reproduce as much as they can, so if one snail has a way of ensuring that its sperm and not others’ is used to fertilize the eggs, it will have advantage over other snails and sire more offspring!

Sperm competition is somehow present. Basically, 2 or more snails can shoot “love dart” at the same partner (they are promiscuous!). The depth of penetration will determine how good the shot is; the deeper the higher amount of sperm stored! Thus, if one snail is better than the other, higher percentage of the newborn will be its offspring since its sperm has greater chances of being selected by the female for fertilization!

2 snails

Sounds cool right? While the “male” can enjoy shooting the “love dart” showing its affection, the recipient would be OOL (ouching out loud). This may be a very horrifying process because the darts are just like hypodermic needle and can rip off the skin of the recipients!  So sometimes snails will try to avoid getting hit on! How apt to human beings relationship, right? =p



“Are Snails’ ”Love Darts” Source of Cupid Lore?” by Ian Popple. National Geographic, February 13, 2002. URL: http://news.nationalgeographic.com/news/2002/02/0213_020213_wiresnail.html (accessed on 5 April 2010)


 Menno Schilthuizen, 2005. The darting game in snails and slugs. TRENDS in Ecology and Evolution 20 (11):581-584.

Janet L. Leonard, 1992. The “love dart” in helicid snails: a gift of calcium or a firm commitment? J.theor.Biol 159:513-521.

Pomiankowski.A and Reguera.P, 2001. The point of love. TRENDS in Ecology & Evolution 16(10):533-534


Dr Ron Chase- Home Pagehttp://biology.mcgill.ca/faculty/chase/ (accessed on 6 April 2010)

The Greatest Lover: Beheaded Male

Praying mantis, Mantis Religiosa, is known for its insatiable appetite of all the hunting ogres of the insect world. They not only hunt other species for food, they also engage in sexual cannibalism where female devours male during courtship or after copulation.

Female mantis would normally seize the male and begin to eat his head and thorax. Even without a head, the male managed to clamber onto the back of the female and successfully copulate with her. With the remains of the thorax and abdomen, the male stayed attached to the female for several hours. Eventually the male would relax his clasp on the female, who finished her meal, leaving only the wings and harder pieces of chitin behind. Surprisingly, during this process the male actually showed great sexual excitement. Milius (1999) in her “Who’s Dying for Sex?” showed Michael R. Maxwell’s observation on the distinct difference in mating duration between two male praying mantises, one with a head and the other without. The former mates for 4 hours on the average while the latter can mate up to 24 hours.

WOW! So how can the headless male not be the greatest lover to the female?

Now the question is why does headless male praying mantis still able to mate?

In mantids, copulatory movements are regulated by masses of nerve tissue in the abdomen instead of the brain. Males mate more efficiently when decapitated as its head has a nerve center that inhibits mating until a female grasps it. When this nerve is removed, it resulted in a loss of control and repeated copulation occurred. Therefore, male continues to copulate while he is being devoured and perhaps, more aggressively!

To me, this is definitely a classic example in which killing the male helps to stimulate reproductive act, isn’t it?



“Headless Males Make Great Lovers and Other Unusual Natural Histories” by Marty Crump. University of Chicago Press, 2005. URL: http://www.press.uchicago.edu/Misc/Chicago/121992.html (accessed on 1st April 2010).


Milius, S. (1999, November 13). Who’s Dying for Sex?. Science News.  156(20): 312 – 314.

Roeder, K. D. (1935, October). An Experimental Analysis of the Sexual Behavior of the Praying Mantis (Mantis religiosa L.). Biological Bullentin. 69(2): 203 – 220.


“Female praying mantis eats male after mating” by dissogtg. YouTube Channel, 9th July 2006. URL: http://www.youtube.com/watch?v=KYp_Xi4AtAQ (accessed on 1st April 2010)