Alright, so I was walking home the other day and suddenly I hear this weird clacking sound behind me. It was approximately 11.30pm and I was freaked. I’m not a ghost-believer but I am scared of meeting crazy, pervy humans in the middle of the night. Rather than turning around to locate the source of that sound, I hastened my leisurely walk to a brisk one. But, whaddya know, the sound seemed to follow me! I whirl around and lo and behold, it was a cat! But the little guy was crouched and looked as though it was ready to pounce! Now, I must admit, I am a cat lover but this cat seemed to come out of Steven Spielberg’s (awesome) film Jurassic Park. It kept making a sort of Velociraptor noise with its mouth. “What’s up little fella?” I asked it (yes I talk to cats). Suddenly, a rat streaked by me and the crazy cat, of course dashed madly after it.

Intrigued by this behaviour, I went online to see if there was some explanation for the cat’s weird sounds. Sure enough, there was. Youtube is a Godsend, seriously. Apparently, the term for that sound is called chatter and cats make that sound when they spot prey. Take a look at this video.

THOSE CATS ARE DINOSAURS!!

I don’t know about you guys, but that sound is sooo weird. It doesn’t sound like anything I would ever associate with cats. There hasn’t been a whole lot of research on why cats make certain vocalizations but there are a lot of pet-associated websites that do explain this chattering sound. Apparently, one of the reasons a cat chatters is because “this is [the] cat’s way of trying to get the prey to trust them” and also one website even said that cats make this sound when they deliver a “special” neck bite to their prey. This “special” bite, I found out, is called a Killbite where it’s basically a forceful bite to the jugular vein in the neck of the prey. These kinds of sounds are also mostly seen in feral cats and noted to be known as instinctive hunting sounds.

Interestingly, cats don’t only make this sound when it comes to prey but can be seen in instances when they are scolded or threatened by humans. An article from StarTribune.com states, “[Cats] will chatter back at their human when they are caught off guard or disagree with the human’s tone of voice toward them. If your cat gets in trouble, sometimes, he will chatter back at you, as if in defence of himself, saying, “Whatever it is, I didn’t do it!””.

Whether or not, these facts are true on cats chatter, I don’t know. Maybe those of you who own cats might try a hand in explaining this phenomenon. Lol. All I know is that, the next time I’m walking home, I don’t have to worry about being stalked by dinosaurs!

P.s. Didn’t you think the squirrel was cute? Looked like it was doing sign language with its tail! Oh well, that’s for someone else to research. Taarah!

Petplace.com. “Why Do Cats Make a Chattering Sound”. Understanding your cat. Virginia Wells. 2009.         <http://www.petplace.com/cats/why-do-cats-make-a-chattering-sound/page1.aspx>

StarTribune.com. “Sounds your cats make have different meanings”. The sounds cats make. 2009. Star Tribune.<http://www.startribune.com/lifestyle/pets/11253316.html>

Hall, Sarah, John, Bradshaw and Ian Robinson. Object play in adult domestic cats: the roles of habituation and disinhibition. Applied Animal Behaviour Science, 79.3. (2002) 263-271.

Killer Whales VS Sea Lions

The video above depicts two killer whale siblings on a hunt for their prey. What is extraordinary about the video is that after they have consumed the daily required intake, they start playing with their prey and return it back to the shore from whence it came. This act of mercy has confounded behavioral scientists alike; instead of just eating the prey or perhaps leaving it to fend for itself, the whales actually brought it back to its original location.

Early descriptions of “whale killers” or “killers of whales” gave rise to the common name killer whale. More in vogue is the name orca, from the species’ scientific label, Orcinus orca, but for those who know Latin, “whale from the underworld of the dead” is hardly an image upgrade. Strictly speaking, orcas are not whales. They are the world’s largest, brawniest dolphins, found in every ocean. With enormous reserves of speed and strength, one of the biggest brains in existence—four times the weight of a human’s—and no natural enemies as adults, they have staked a claim as the supreme predators across 71 percent of the planet. What do they do when they meet a great white shark? Lunch, according to witnesses.¹

They feast on marine mammals such as seals, sea lions, and even whales, employing teeth that can be four inches (ten centimeters) long. They are known to grab seals right off the ice. They also eat fish, squid, and seabirds. Though they often frequent cold, coastal waters, orcas can be found from the polar regions to the Equator. Killer whales hunt in deadly pods, family groups of up to 40 individuals. There appear to be both resident and transient pod populations of killer whales. These different groups may prey on different animals and use different techniques to catch them. Resident pods tend to prefer fish, while transient pods target marine mammals. All pods use effective, cooperative hunting techniques that some liken to the behavior of wolf packs.²

The act of mercy as shown in the video has not been restricted to only killer whales. Other species have been known to exhibit this tendency too. Foxes have been known to play with captured prey after they have satisfied their necessary daily intake. In the book Animal Minds, the Author Donald Griffin describes an observation of a six-month old red fox who extensively appeared to release a captured shrew intentionally and return it to the vicinity of its burrow. This fox had caught and immediately eaten one mouse, then caught another with which he “played vigorously for several minutes”. After it had been killed the fox carried it some distance and cached it.

Although this showed he was no longer hungry, he soon captured a shrew, which he carried some distance to an open roadway where he began to play with it. The fox’s behaviour was also described as leaping around, dancing about the shrew who runs over to one side of the road before the fox herds it back to the center. After 45 seconds of playing with the animal, the fox does an extraordinary thing. He picks the shrew up in his mouth, walks back down the slope to where he captured the prey and then with a toss of his head spits the shrew out directly at a small burrow. Perhaps there is the possibility that animals cache their food in order for future perusal, instead of trying to eat everything in sight. ³

Humans could learn a thing or two about greed, or the lack of it from these creatures. The symbiotic nature of the environment would definitely have a role to play in explaining such phenomena and we could take our cues from the animal kingdom in a bid to stave off world hunger perhaps?

More information on Killer Whales:

• http://www.seaworld.org/animal-info/Animal-bytes/animalia/eumetazoa/coelomates/deuterostomes/chordata/craniata/mammalia/cetacea/killer-whale.htm

• http://www.seaworld.org/animal-info/info-books/killer-whale/diet.htm

Videos On Killer Whales hunting Prey:

• http://odeo.com/episodes/23491062-Animals-Attack-Killer-Whale-vs-Sea-Lion

• http://news.bbc.co.uk/2/hi/science/nature/7940208.stm

^References

I love animals. I love them most when they are furry and warm, with whiskers and cute paws and small legs. Who can resist a bunny rabbit hopping around your legs begging you for food? Or a kitty cat snuggling into your arms for a rest? They’re simply irresistible. To do a write up about these cute animals, I might as well be setting up a website like cuteoverload.com, with pictures of baby rabbits, puppies and puggles. So on the contrary, I have decided to do a write up on the most disgusting creature I came across. This creature is by far the most heinous and repulsive, in all aspects, from its physical appearance, to its feeding habits, reproduction and most of all its defence mechanism! I present to you, the Atlantic Hagfish, also known scientifically as Myxine Glutinosa

The hagfish looks like an eel. In fact, it is very often mistaken for an eel and scientists have even debated whether or not it belonged to the fish family or the lampreys. It is the only animal with a skull but no backbone. Picture it as an underwater snake, if you will, with barbels (whisker like organ) instead of fins and a single nostril. Its colour ranges from grey to pink or brown, depending on the species and is found at a depth of 4000 feet underwater, making it a deep sea creature. The Atlantic Hagfish, as its name might suggest, is found on both sides of the North Atlantic Ocean and can go as far up as Norway.

If its appearance is not enough to repulse you, it’s feeding habits might. Albeit relatively small (16 -32 inches), the hagfish possesses a very barbaric and monstrous way of feeding. The hagfish starts off by attaching itself to another healthy fish. Unlike the Remora, the Hagfish does not stay at the sides or underneath its host, feeding on its remains, but bores its way into the host fish. The hagfish then feed on the host fish’s flesh with its tongue, literally eating its host inside out. There are instances where deep-sea fishermen found thousands of hagfish (instead of flesh) inside their catch! Be careful the next time you’re eating a Cod.

Sex with the Hagfish can be confusing. This is because some are hermaphrodites. Yes, they have both male and female sexual organs. A study conducted by Scott I. Kavanagh et Al in 2004 revealed that the production of gonadotropin-releasing hormone is highly seasonal and differs in relation to its size class and stage of gonadal development: “In the medium and large class hagfish, there was an increase in GnRH concentrations during April and May that correlated with male and female gonadal maturity. Also in these size classes of female hagfish, there was a similar rise in GnRH in November and then again in January that preceded the highest incidence of large eggs.”

What is known is that the hagfish’s eggs attach together and the Hagfish will curl itself around the eggs but it is not known if they are taking care of the eggs.Sexual Reproduction in the Hagfish is rarely documented and further study is much needed to those who can withstand its slime and grime.

Yes, the most disgusting fact about the Hagfish? Aside from its confused sexual orientation, its beastly eating habits and its unsightly appearance, the Hagfish is known for its defence mechanism. The slime. When provoked, the Hagfish excretes a whitish substance that, when in contact with water, will develop into a thick, slimy substance that reminds you of your own mucus! A Study by S.Subramanian et Al., discovered that a major constituent of the hagfish extruded slime are trypsin-like proteases. They found that stress induced slime of the Hagfish contains “various innate immune parameters in comparison to its epidermal mucus”. The slime excreted from the hagfish not only protects it from its predators (thickness of the slime clogs predators’ gills), but also from other diseases and micro organisms that might cause infection! Interestingly, the hagfish escapes from its own slime by knotting itself up and pushing this knot through its body.

The video below shows a scientist and his research animal: the hagfish.

If the video doesn’t load, click here to view: Hagfish Slime

Look at how just a teeny bit of excretion did to a beaker of distilled water! Do not underestimate the power of slime.

References:

Scott I. Kavanagh, Mickie L. Powell, Stacia A. Sower, (2005) “Seasonal Changes of Gonadotropin-releasing Hormone in the Atlantic Hagfish Myxine Glutinosa” General and Comparative Endocrinology, Volume 140, Pages 136-143.

S. Subramanian, N.W. Ross, S.L. MacKinnon, (2008) “Comparison of the biochemical composition of normal epidermal mucus and extruded slime of Hagfish (Myxine Glutinosa)” Fish & Shellfish Immunology, Volume 28, Pages 625 – 632

http://www.seasky.org/deep-sea/atlantic-hagfish.html

http://en.wikipedia.org/wiki/Hagfish

Non-human primates(monkeys) have been touted as the closest animal kin to human beings. Studies on the tool-using behavior of long-tailed macaques (Macaca fascicularis) in Thailand shows that we have more in common than we probably realise.

In the old Buddhist shrine of Prang Sam Yota, Lopburi, Thailand, female long-tailed macaques have been observed to floss using human hair pieces, doubling the time spent flossing when their infants are in proximity. This suggests that the mothers are intentionally passing on the skill to their young (also known as tool use learning).

“I was surprised because teaching techniques on using tools properly to a third party are said to be an activity carried out only by humans,” said Professor Nobuo Masataka. (BBC 2009)

Fig. 1.(Taken from Watanabe, Urasopon, Malaivijitnond 2007;942)
A monkey using hair for dental floss (top, left and right), juvenile monkey using coconut shell fiber (bottom left) and pulling women’s hair (bottom right).

The macaques displayed an amazing amount of consciousness over the act of flossing, showing an uncanny similarity to such human actions. To floss, the macaque has to sort through hair lengths, hold the string taut before edging the hair between teeth and finally pulling it off to one side to remove lodged bits of food. “Reinsertion’ of the make-shift floss is also noted. In addition, fibers from coconut shells were similarly used (Fig. 1).Flossing was notably prolonged when baby macaques are nearby. The magnification or ‘looming’ of a particular action (also known as motionese) enhances the transmission of cultural information, accounting for the ubiquity of macaques flossing near the temple site.

It is interesting to note that when presented with hairpieces, some macaques appear to remove only a few strands of hair, demonstrating an awareness of the type of tool they require for the task (similar to how people break off an appropriate length of floss from the spool of dental thread). Also, since monkeys cannot see what they are doing, they have to rely on tactile senses to fine-tune and readjust the flossing process, just as we do. (video: Mother Monkey flossing)

This atypical behaviour of the macaques is attributable to the unique environment that the monkey live in. [Kawai, 1965] The religion of the people in the Lopburi area views monkeys as servants of God, offering up huge amounts of foods every day. The worship of these shrine monkeys explains why the monkeys have been able to survive in the city area and allows them to engage in activities that would not be tolerated otherwise.

Monkeys ‘teach infants to floss’, BBC. 12 March 2009.

Monkeys That Floss With Human Hair Learn From Mom?, Charles Q. Choi. National Geographic News,12 March 2009.

Kunio Watanabe, Nontakorn Urasopon, and Suchinda Malaivijitnond, 2007. Long-tailed macaques (Macaca fascicularis) use human hair as dental floss. American Journal of Primatology, 69; 940-944.

Masataka N, Koda H, Urasopon N, Watanabe K, 2009. Free-Ranging Macaque Mothers Exaggerate Tool-Using Behavior when Observed by Offspring. PLoS ONE 4(3): e4768. doi:10.1371/journal.pone.0004768Kawai M., 1965.

Newly acquired pre-cultural behavior of the natural troop of Japanese
monkeys on Koshima Islet. Primates 6:1–30.

Praying Mantis, Mating

IS sex always a good thing? Unfortunately Male Praying Mantis says NO. This is because Female Praying Mantis consume the head (and sometimes the rest) of her mate during copulation. Yes i know what you are thinking. Even nymphomaniacs squirm at this thought.

Praying Mantis have a carnivorous appetite that include moths, crickets, flies, grasshoppers and other insects as well. These insects are also prone to eating others of their own kind. The most famous example of this is the notorious mating behavior of the adult female, who sometimes eats her mate just after-sometimes during- mating.

Yet this does stop the males from courtship and mating. The most common courtship of the males would be when he approaches the female frontally, slowing his speed as he nears. The second most common courtship is when the male approaches the female from behind, speeding up as he nears.

But research has challenged this notion of sexual cannibalism among the praying mantis. Eckehard Liske and W. Jackson Davis made videotapes of sex lives of 30 pairs of praying mantises. They discovered that the none of the 30 male mantises had their heads eaten during the mating process. Although female mantises sometimes ate their mates, the deadly act by no means occurred in every case. They observed that the behavior is influenced by captivity: Female mantises became unusually became aggressive thanks to the unusual laboratory conditions and feeding times observed by the researchers.

Yes, the female praying mantis does sometimes eat the male. In fact, it is the male mantises who actually want to offer themselves as food. There is a simple, yet, rational explanation behind it. That is, there is no point in having sex if she is going to die of starvation before she can lay eggs and pass the father’s genes onto the next generation. Some might call this True love.

Now, Guys, how far are you willing to go to sacrifice your lives for true love?

Reference:

“The Female Praying Mantis: Sexual Predator or Misunderstood” by Doughty Michele, Biology 103, 2002 First Paper, http://serendip.brynmawr.edu/exchange/node/1801

Praying Mantis by National Geographic http://animals.nationalgeographic.com/animals/bugs/praying-mantis.html

Liske, E.; Davis, W.J.(1984) Sexual behaviour of the Chinese praying mantis v. 32(3): 916-918

A study done on guppies from the Trinidad River, by Dr. Croft, suggests that the female guppies were being sexually harassed by the males, which has thus caused the females to traverse the waters of the predator to dodge this harassment. Observation indicates that the harassment stems from the male that were rejected by the females.[1] Such an observation ought to be read via the perspective of sexual selection. In an attempt to produce strong offspring, sexual selection occurs where the females only mate with the colourful males, where bright colours are an indication of the males’ attractiveness and high quality.[2] Such acts of sexual selection have thus resulted in the rejected male guppies attempting, “…to sneak a mating with his chosen female when she is not looking.”[3] This has therefore led to the female guppies’ presence in the waters filled with predators, which would keep the harassing males away as their bright colours will make them an easy prey for the predators.

            The lens of sexual segregation ought to be employed to read deeper into such behaviours among the female guppies. “Sexual segregation has been defined traditionally as the differential use of space (and often habitat and forage) by sexes outside the mating season”[4] Given this definitional framework, it is now possible to advance a hypothesis to explain the female guppies’ behaviour. Terry Bowyer advanced one that attributed sexual segregation to the need by females to competitively exclude the males.[5] However, this hypothesis may be location-specific and may not hold true for the guppies from regions outside the Trinidad River.

            This therefore calls for an alternative hypothesis, which can encompass all female guppies by accounting for such behaviours among them. The alternative hypothesis suggests that the female guppies are not reliant on some seasons as they produce relatively few eggs and give birth to live offspring.[6] This implies that the females’ ultimate aim is to ensure that they produce strong offspring (which occurs from mating with high quality males). This aim is further reinforced by the fact that they live in the waters infested with predators to prevent sexual harassment and unwanted mating, even with the high quality males, given their non-reliant seasons.

            As much as the females may aim to produce strong offspring, the ecosystems are such that the predators are the first to go extinct. [7] Thus, while the females may have gone to the waters of the predators to fend the sexual harassment of the male, the realities of the ecosystem may not favour their presence in the predators’ waters. As such, mating may occur inevitably in the predators’ water with less colourful males as they are not as prominent as the brighter coloured ones, which run higher risks of predation in the predators’ waters. Hence, sexual selection (choosing of high quality males) may not occur and this would result in weaker offspring. The possibility of producing weaker offspring can be further vindicated by the studies done in the Savannah River Ecology Laboratory, which concluded that female guppies are less choosy when predators are present.[8]

            Hence, sexual segregation by female guppies in the form of their residence in the waters of the predators to fend sexual harassment from the rejected males and preclude unwanted mating during their non-reliant period, which is aimed at ensuring the production of high quality offspring, is not favoured by the ecosystem. Given the ecosystem and their limited choice when predators are present, sexual selection among the guppies becomes constrained and thus leads to the production of weaker guppies. Hence, the initial purpose of sexual segregation by traversing the waters of the predators is defeated by the reality of the waters of the predators itself. Despite sexual segregation, the female guppies still get harassed by the males and the quality of their offspring witnesses a plausible degradation.

A typical clown anemonefish swimming between the tantacles of the sea anemone coral

So you think you have found ‘Nemo’ and know all about it after watching the animation by Walt Disney Pictures - Finding Nemo? Not just yet! There are more to this fish than meets the eye.

More commonly known as clown fish, it is actually called the clown anemonefish, that is where the name ‘Nemo’ came from. There are several interesting facts about this fish which makes them so different from other fishes:

• The ‘Nemo’ in the movie belongs to the group called the false anemonefish. The other group called the true anemonefish, lives mainly within the stinging tantacles of the sea anemone coral (which is also an animal), which can paralyse any intruders upon contact.
• The clownfish, together with the anemone coral, forms a formidable partnership, attacking and consuming every intruder.
• The anemonefish have a layer of mucus around their body protecting them from the stings of the coral they lived in.
• They live in groups of up to 6, led by a dominant female
• They are all born as males, but when the need arises, they can change into female.

Surprisingly, all clownfish are born male. They have the ability to switch their sex, but will do so only to become the dominant female of a group. The change is irreversible.

Behaviour Analysis:

Territorial: In the case of this Clown Anemonefish, we can see the sea anemone coral as its ‘territory’.  With this partnership between the fish and the coral, both benefits greatly from each other’s presence. From the fish point of view, it aquire food, as well as shelter or protection from the stinging and poisonous tantacles of the coral. This belongs to the type of territory: Mating, nesting and feeding.

Living in groups: The clown anemonefishes live in groups that resemble a herem, except that it is the opposite. Led by a large dominant female with her chosen mate, the rest of the (up to) 4 ’subordinates’ are all male (because all anemonefishes are born as males). When the dominant female dies, a smaller subordinate male fish will put on a growth spurt and change of sex to take its place as the ‘herem’ leader.

Links:

• National Geographic Website article: Clown Anemonefish
• Article published on Nature, 25th August 1934: Partnership between Fish and Anemone
• Article on Nature website, 10th July 2002: Clownfish know their place

References:

• “Clown Anemonefish” on National Geographic Website: http://animals.nationalgeographic.com/animals/fish/clown-anemonefish.html
• “Partnership between Fish and Anemone” by H.A.F. Gohar. Nature, 25th August 1934.
• “Clownfish Know their Place” by John Whitfield. Nature Online, 10th July 2002.
• Picture from photine’s Flickr: http://www.flickr.com/photos/laanba/3235778429/sizes/m/

While we are eating our sambal sotong at a seafood restaurant by the beach, enjoying the sea breeze, it is a harsh world out there deep under the sea. The ’sotongs’ have a tough decision to make, either they lay their eggs deep in the sea on the ocean bed leaving them vulnerable to predators, or they carry the eggs around and after hatching, the exhausted mothers themselves are left vulnerable to predators. The catch: the eggs comes in thousands, often the combined size of all the eggs are way larger than the body of a single mother squid.

Most species of squid opted for the first. During mating season, they dive deep into the sea and lay their eggs on the ocean floor, leaving them to hatch on their own. However, scientists discovered recently, that the Gonatus Onyx decided to trade their own survivability for that of their young.

This squid, Gonatus Onyx, was discovered to be taking care of its eggs instead of leaving them lying around the ocean bed, waiting to be eaten up.

“Laying eggs on the ocean floor is quick and costs little in terms of energy; the penalty is a lowered chance of survival for the young.

Carrying the eggs around is far more expensive in energy terms, and does seem to affect the mothers severely. “

Links:

The link to the article on BBC News – Science\Nature: First images of baby squid care

A short one-page scientific article published on Nature: Post-spawning egg care by a squid (requires logging on to NUS account)

The full scientific paper on Gonatus Onyx: Life history of Gonatus onyx (requires logging on to NUS account)

Analysis:

This behaviour that we’re looking at actually comes from the fight for survival. Because the Gonatus Onyx is one of the most common squid in the Pacific and Atlantic ocean, they are also being highly predated on. This became a cost vs benefit situation, which over time, has evolved into the current state.

Cost: mother squid spend more time and energy taking care and protecting the eggs by carrying them around. After the the eggs hatched, the mother squid herself became weak and thus more vulnerable to predators.

Benefit: The chances of survival of the thousands of baby squids increased greatly.

Conclusion: The mother squid sacrificed itself for the survival of its babies. She traded her own life for thousands of her offsprings to survive. In this case, the benefits of this behavior greatly outweighs the cost, hence the population of Gonatus Onyx will continue to thrive.

References:

• “First Images of Squid Care” by BBC News, Science/Nature. 15 dec 2005. http://news.bbc.co.uk/2/hi/science/nature/4530980.stm
• Seibel, B.A., F.G. Hochberg & D.B. Carlini. 2000. Life history of Gonatus onyx (Cephalopod: Teuthoidea): deep-sea spawning and post-spawning egg care. Marine Biology 137(3): 519-526.
• “Post-spawning egg care by a squid” Brad A Seibel; Bruce H Robison; Steven H D Haddock. Nature, Vol 438: pg. 929
• Picture from: http://tolweb.org/onlinecontributors/app?service=external/ViewImageData&sp=11834

Truly the stuff of Hollywood ‘animal horror’ flicks, the red-bellied piranha (Pygocentrus Nattereri), with its bulging eyes and razor-sharp teeth, have gained enough notoriety to rival the shark as the most-feared fish in the sea (aside from the fact that they don’t actually live in the sea, but rather in the rivers of the Amazon). Seen in a trailer of Discovery’s Animal Planet Series, River Monsters, a shoal of piranhas swarm and finish off half a duck carcass in a scarcely a minute. Definitely not something that you would like to find in your bathtub!

The scent of blood and the thrashing of an injured animal (or human!) in the water typically triggers off a feeding frenzy in the shoal, which results in several dozens or even hundreds of piranhas descending upon its hapless victim, completely devouring it in a matter of minutes. The piranhas can accomplish this scary but amazing feat mostly because their jaws of interlocking teeth tear easily into flesh, which they literally rip off and swallow without chewing. Once tearing off a chunk of meat, they move out of the way to make way for the next fish in line to get its bite. As a result the shoal efficiently demolishes off the unfortunate creature, leaving behind little more than skeletal remains.

Paul A. Zahl/National Geographic/Getty Images

Thankfully, such frenzies only occur when there is easy prey (old, sickly or injured animals) to be had, or when the piranhas have been starved and are really, really hungry. Under normal circumstances they rarely attack large, healthy animals (such as people), and mostly feed on other small fish and carrion. In fact, their role as scavengers(and not predators) is paramount to the Amazon’s ecosystem, as they very efficiently clean up any dead creature long before decay sets in, keeping the waters habitable for other marine life.

Contrary to what Hollywood would have us believe, piranhas are actually pretty wimpy creatures, considering that they live in the big bad (and very wild) Amazon. Originally thought to form shoals in order to effectively overwhelm and take down large animals, it turns out that the piranhas huddle together for predator defence instead; to take advantage of safety in large numbers, just like normal fish. And who would predate on the jaw-chomping, frenzy-feeding piranha? Just about anyone bigger than itself, it seems. Piranhas make tasty snacks for river dolphins, caimans, aquatic birds, and larger fish.

Looks like there’s always a bigger fish in the sea, isn’t there?

Claus Meyer/Minden Pictures/Getty Images

References:

“Can Piranhas really strip a cow to the bone in under a minute?” by Julia Layton. Howstuffworks. Accessed April 2009.

“Piranha Devours a Duck“. AnimalPlanetTV. April 2009.

Pauly, D. 1993. “Quantitative analysis of published data on the growth, metabolism, food consumption, and related features of the red-bellied piranha, Serrasalmus nattereri (Characidae)” Environmental Biology of Fishes, 41: 423-437.

Queiroz, H. & Magurran, A.E., 2005. “Safety in numbers? Shoaling behaviour of the Amazonian red-bellied piranha” Biology Letters, 1 (2): 155-157.

A group of captive killer whales have come up with a strategy to snack on seagulls to supplement their diet… or boredom.

An enterprising young killer whale began using a new baiting tactic to add seagulls to his menu. After feeding time, when his keepers had fed him with fish, this intelligent mammal would regurgitate some of them onto the water surface and then sink below to wait. If a hungry gull landed on the water, he would rush toward it and catch the unsuspecting bird in one maw.

What’s more, he has taught his fellow whales how to do it. As he set his trap again and again with success, his younger half brother began to adopt the practice after a few months.

‘”It looked liked one was watching while the other tried,” Professor Noonan, who made the discovery, said of the whale’s initial behavior.’

The capacity to come up with the baiting strategy and share the technique with others is known as cultural learning in the scientific world. Once, it was believed to be one of the abilities that separated humans from animals. Now it seems on top of other dolphins and chimpanzees, killer whales are also capable of such gifted behavior.

References

“Whale uses fish as bait to catch seagulls then shares strategy with fellow orcas.“ AP, 7 Sep 2005. Retrieved http://news.mongabay.com/2005/0907-ap.html

Rendell, L. and Whitehead, H., Culture in whales and dolphins. Journal of Behavioral and Brain Sciences (2001), 24:309-324