zoo:logic

New research has shown that Atlantic salmon (Salmo salar)...

Wed, 30 May 2012 13:39:00 +0100

New research has shown that Atlantic salmon (Salmo salar) experience a feeling akin to frustration when they are not given a reward they are expecting to receive - a response previously only observed in mammals and birds. Debates over the ethics of fishing often throw up questions of whether fish are ‘conscious’ and have an awareness of pain, which has fuelled a fair amount of research in the area. Fish have been shown to be capable of responding to classical conditioning and to have long-term memories; however, we are still unsure to what extent their cognitive abilities are linked to conscious moods and emotions. This concept was studied in the salmon using a model commonly used in mammalian research called omission of expected reward (OER). In these experiments, animals are conditioned to associate a certain stimulus with a positive reward, such as food, and are then subjected to the stimulus without receiving the reward to record how they react. In mammals, OER has consistently been shown to cause animals to become stressed and aggressive.

Six groups, each consisting of 200 fish, were conditioned to associate a flashing light with feeding over a period of 22 days. By the end of this period, the fish showed attraction to the light due to association with the food reward, as opposed to their initial reaction of avoiding it. Three of the groups were then subjected to OER for 9 days - the fish were fed three times a day, and at two of these mealtimes, the expected food reward was delayed by 30 minutes. The other three groups carried on as normal, acting as controls.

When the groups were compared, OER groups showed higher aggression and greater hierarchy, causing some individuals to grow more quickly at the expense of others - interestingly, even during the one meal a day when the reward was provided immediately, aggression levels remained high. Stress levels were measured by detecting the concentration of cortisol (a hormone which is involved in stress response) in the blood, but unlike the variation seen in aggressive behaviour, these were the same across all groups, suggesting that although there were behavioural signs of stress this did not translate to a physiological stress reaction.

There are two possible explanations for the variation in aggressive behaviour:
- Dominant individuals may be trying to keep their position for prime access to food in expectation of the coming reward
- Aggression triggered by the stressful situation may be being displaced towards other individuals to help in coping with the conditions.
In either case this leads to stronger hierarchy and more uneven distribution of resources, as was observed in this study.

The overall conclusion is that fish respond behaviourally to frustrating conditions just like birds and mammals, suggesting this could be an adaptive response to unpredictable environments that has been conserved throughout vertebrate evolution. While we cannot yet conclude that fish definitely experience conscious emotional states, the results do highlight the importance of regular routine for domestic or farmed fish in order to reduce aggressive interactions between individuals that may be detrimental to the health of the population.

Ref: Vinas M. A. et al., 2012. Omission of expected reward agitates Atlantic salmon (Salmo salar). Animal Cognition Online first [link]

blue-shark009: My favorite animal is the water bear! They can...

Tue, 29 May 2012 00:19:55 +0100

blue-shark009:

My favorite animal is the water bear! They can survive extreme heat and cold, radiation levels, they can survive hundreds of years without food or water, and they can survive in space!! I think water bears beat koalas Hands down!

Ah, finally someone with a more unconventional favourite! And what a fabulous choice. There are hundreds of reasons why water bears (Tardigrada) are amazing animals. Tardigrades (meaning “slow walker” in Latin) are a phylum of over 1000 different species that are found everywhere in the world - from Himalayan peaks of over 6000 metres to ocean depths below 4000m, from icy polar regions to the heat of the tropics, in freshwater, saltwater and damp terrestrial habitats. If you’re wondering why such an abundant creature has so far escaped your notice, it’s because they are at their greatest 1.5mm and at their smallest, just 0.1mm long. But don’t dismiss them yet - they are most certainly one of the cutest and most interesting microscopic organisms out there!

Water bears have a body with four segments and four pairs of lobopodial (unjointed) legs each bearing a set of 4-8 little claws. They feed using a stylet, or small tube, with which they pierce plant or animal cells and then suck up the internal fluids. Of the many species of water bear, some are purely carnivorous, consuming bacteria, rotifers or other tardigrades, some are omnivorous, and some are herbivorous, eating only plant materials.

The most famous and interesting characteristic of water bears is that they can enter a state known as cryptobiosis if environmental conditions become insufficient to live in. In cryptobiosis, the tardigrade dries up into a form known as a ‘tun’ (containing less than 1% water) and its metabolic rate drops to a hundredth of a percent of its normal rate or may even be completely undetectable. It can remain like this for up to 100 years and only takes a few minutes to come ‘back to life’ once returned to favourable conditions! Cryptobiosis has a number of different triggers that activate slightly different pathways. These are drastic changes in water solute content such as ion concentration (osmobiosis), drought (anhydrobiosis), extreme temperatures (cryobiosis) or lack of oxygen (anoxybiosis). In their natural environment, the most common form of cryptobiosis is anhydrobiosis, but we’ve conducted all sorts of crazy experiments to see what else they can survive. They have sailed through several minutes at 151ºC, and several days below -200ºC. They can withstand extreme radiation at levels that would be lethal to almost all other animals. And tardigrades have even ventured into space, surviving 10 days of vacuum and cosmic radiation with 68% still retaining the ability to live and reproduce (the project is called TARDIS which just makes it all the better). Not only can they survive very low pressures as in the vacuum of space but also very high pressures, more than 1200 times greater than atmospheric pressure!

Finally, as with any great character the water bear even has its own cuddly toy. What more could you want from a favourite animal?!

Ref: Shifflett B. M., 2008. Tardigrades. University of Wisconsin Organismal Biology [link]
Lindahl K. & Balser S., 1999. Tardigrade Facts. Illinois Wesleyan University [link]
Goldstein B. & Blaxter M., 2002. Tardigrades. Current Biology 12(14):475. [link]
Wikipedia

Now listed on ScienceOn!Tumblr!

Mon, 28 May 2012 18:48:17 +0100

zoo:logic can now be found listed in the directory of tumblr’s science-based blogs over at ScienceOn!Tumblr. What a great idea and full of fantastic blogs - any science bloggers that haven’t yet submitted themselves should do so, and anyone interested in any form of science should head over there and check it out!

skaterboytae: When a honeybee dies it releases a death...

Sun, 27 May 2012 18:08:22 +0100

skaterboytae:

When a honeybee dies it releases a death pheromone, a characteristic odor that signals the survivors to remove it from the hive. This might seem a supreme final act of social responsibility. The corpse is promptly pushed and tugged out of the hive. The death pheromone is oleic acid [a fairly complex molecule, CH3(CH2)7CH=CH(CH2)7COOH, where = stands for a double chemical bond].

What happens if a live bee is dabbed with a drop of oleic acid?

Then, no matter how strapping and vigorous it might be, it is carried “kicking and screaming” out of the hive. Even the Queen bee, if she’s painted with invisible amounts of oleic acid, will be subjected to this indignity.

Do the bees understand the danger of corpses decomposing in the hive? Are they aware of the connection between death and oleic acid? Do they have any idea what death is? Do they think to check the oleic acid signal against other information, such as healty spontaneous movement? The answer to all these questions is, almost certainly, No. In the life of the hive there’s no way that a bee can give off detectable whiff of oleic acid other than by dying. Elaborate contemplative machinery is unnecessary. Their perceptions are adequate for their needs.

Ann Druyan & Carl Sagan, Shadows Of Forgotten Ancestors: Who Are We?, What Thin Partitions

What is your favourite animal and what is it about them that you think makes them so incredible?

Sat, 26 May 2012 21:54:49 +0100

iloveeucalyptus:

Land animal - koalas

Aside from the adorable factor, and I mean…come on

Their evolution is amazing. It’s one of those species that truly filled a niche that nothing else occupied (eucalyptus eater). Also, fun fact, they have two, fully functional versions of their respective reproductive organs. No one knows why, but it’s still really cool (they aren’t the only animals with this, I believe it’s not an entirely uncommon thing in marsupials). Their vocalizations sound like you’ve just summoned something from hell and it was extremely displeased with the transfer.

And they have their own urban legend, drop bears. Really, there isn’t anything to dislike about them.

This post from iloveeucalyptus is great. The koala (Phascolarctos cinereus) is named after an Aboriginal word meaning “no drink”, as they gain all of their water needs from their diet - leaving their home in the trees to reach terrestrial water sources would be too dangerous being such a slow and defenceless target. They are not actually bears, but marsupials, born very immature and spending around 6 months developing in their mother’s pouch. As mentioned above, koalas have a specialised niche living on a diet of toxic, very fibrous and low nutrient eucalyptus leaves that they have to spend most of the time sleeping - up to 18 hours a day - in order to digest. The ability to resist the toxic nature of eucalyptus is passed on through a substance called ‘pap’ that the joeys consume while in their mother’s pouch, which is a specialised form of the mother’s waste that passes on essential microorganisms from their digestive system to the young. They also have an exceptionally long caecum (digestive organ that breaks down plant materials) at around 2m in length! The “drop bear” urban legend that was mentioned is a fictitious form of koala that is much larger, more vicious, and is carnivorous, attacking its victims by dropping onto their heads from above. I don’t know about you but any koala of the real kind is welcome to drop from above and come along for the ride if it’s anything like the cute little guy in the animation posted here!

Ref: Australian Koala Foundation. About Koalas: Interesting facts. [link]
National Geographic. Koala. [link]

The International Institute for Species Exploration at Arizona...

Sat, 26 May 2012 12:38:54 +0100

The International Institute for Species Exploration at Arizona State University has come together with a committee of scientists from around the world to compile a top 10 list of new species discovered in 2011. The choices encompass a range of incredible organisms, from fossilised specimens of a curiously shaped lobopod named the “walking cactus” to a new species of snub-nosed monkey from Myanmar that sneezes when it rains. But my personal favourite is the parasitic wasp Kollasmosoma sentum shown in this video. These wasps cruise along at around a centimetre above ground, looking for their desired hosts: ants of the species Cataglyphis ibericus. When a host is found, the wasp dive-bombs towards it and deposits an egg within the space of just 0.052 seconds on average! The interaction may be brief but it is catastrophic for the ant, which will then become the food source for the growing larvae once the eggs hatch. Parasites are so interesting - it’s amazing how some species have evolved such ingenious adaptations in order to exploit others for their own survival.

Click here to find out more about all of the top 10.

foolishlycompassionate said:I love giraffes! They’re...

Thu, 24 May 2012 13:19:00 +0100

foolishlycompassionate said:
I love giraffes! They’re amazing; they have the same number of vertebrae as humans, which is seven! Their vertebrae however are much larger of course, I believe about 11 inches each!

giraffesanddoxies said:
giraffe!!! they have the same number of vertebrae as humans just much larger! plus just look at em! They’re awesome!

crystimarie said:
Giraffes
- There are 3 different pattern types
- Have you ever watched a giraffe run?
- They only have 7 vertebrae to make up that long neck of theirs
- Their kick can decapitate an African Lion instantly!
- Most they sleep in a day is 2 hours in 20 minute shifts
- Babies alone are born at least 6 feet tall

————————————————————————————-

It’s not surprising giraffes (Giraffa camelopardalis) have been popular as a favourite animal: they are undeniably an amazing feat of evolution. Giraffes are the world’s tallest mammal, with bulls standing 5.7m from the top of the horns to the ground - though they are actually only around 3.3m high at the shoulder, making their necks an incredible 2.4m long. As has been pointed out, this is made up of just 7 elongated vertebrae. Their tongues are also nearly half a metre long!! Despite their size, giraffes can survive on little water and in desert habitats gain most of their moisture from condensation on leaves.

In order to transport blood up the long neck to the brain, giraffes have a blood pressure that is double that found in humans and a heart that beats twice as many times per minute. The heart isn’t particularly large but the left ventricle is surrounded by incredibly thick walls in order to maintain high pressures. The thickness of the muscle wall is related to the length of the neck - for every 15cm increase in neck length, muscle thickness increases by half a centimeter. The legs are protected from the pressure of fluid pressing down on them by tightly-fitting, thick skin that acts much like a pilot’s G-suit.

Having seen giraffes in the wild in South Africa what is most amazing about them is to watch them run, as was mentioned by crystimarie. While they cover ground at a fast rate and reach speeds of up to 40mph, they actually appear to move in slow motion - it honestly feels like a trick of the mind to watch! A good video of this can be seen here.

Ref: Maisano S., 2006. Giraffa camelopardalis. Animal Diversity Web [link]
Giraffe Conservation Foundation, 2011. Giraffe - The Facts. Giraffe Conservation Foundation [link]

Thanks for all your great responses!

Thu, 24 May 2012 12:36:58 +0100

Keep them coming!

For those whose choice is based on the appearance of an animal, if you have the interest, I would recommend digging a little deeper into what makes them great. You’ll be surprised what you might find out! If it’s because they’re intelligent, what exactly can they do that shows that? Often when you go beyond the basics you’ll discover things that open your eyes and may even completely change your opinion about which kinds of animals you find most amazing.

Tell me about your favourite animal

Let's try for some interaction with you lovely people!

Wed, 23 May 2012 23:41:00 +0100

I want to know…

What is your favourite animal and what is it about them that you think makes them so incredible?

Preferably wild rather than domesticated, though if you have a particularly interesting logic for an obsession with a domesticated species, go ahead!

I’ll feature some of my favourites as we go along :) I’m looking to learn some new and interesting things and be inspired by all you guys here! Answers can be put in my ask box or posted to your blog with the tag #”zoo logic” so I can track them.

3…2…1… go!

In an extraordinary biological study, researchers have used...

Wed, 23 May 2012 22:57:00 +0100

In an extraordinary biological study, researchers have used chemical analysis to demonstrate that ink preserved in the remains of two cephalopod fossils that date over 160 million years ago to the Jurassic period is almost identical to that used by modern common cuttlefish (Sepia officinalis) today. The cephalopod fossils were found at sites in Christian Malford, Wiltshire (162 million years old) and Lyme Regis, Dorset (195 million years old) in the UK and included preserved three-dimensional ink sacs. Biological tissues rarely survive in fossilised material as they are almost always quickly degraded by microorganisms. But some types of organic substances found in living organisms may last for long periods of time if they are polymeric - large and made up of multiple subunits - and have a tough cross-linked structure. One such substance is melanin, of which the form eumelanin - which takes a dark black or brown colour - is known to be a key chemical component of modern common cuttlefish ink. Cephalopods use the dark-coloured ink to reduce visibility when threatened so they can rapidly escape without being caught. Mucus is also sometimes added to the ink allowing it to hold a form for a limited period of time, giving the illusion of ‘false bodies’ that act to distract predators from the real organism. Eumelanin remains were found to be well preserved in the ancient fossilised ink sacs through a number of different chemical tests. The maintenance of ink chemical composition over this huge period of time suggests that the use of ink as an anti-predator strategy has retained its evolutionary benefit for well over 160 million years and is fully optimised for its purpose.

Ref: Glass K. et al., 2012. Direct chemical evidence for eumelanin pigment from the Jurassic period. PNAS Online before print [link]

Revising in the garden was a bad idea.

Tue, 22 May 2012 17:40:00 +0100

Revising in the garden was a bad idea.

What a beautiful day! I’d be quite happy in the garden all...

Tue, 22 May 2012 13:28:44 +0100

What a beautiful day! I’d be quite happy in the garden all day long with my camera. Sadly, I’ve got revision to be doing. After tomorrow morning’s exam I’ll be able to go out and enjoy it!

by zoo:logic Lots of new followers, hello :) sorry it’s...

Fri, 18 May 2012 15:26:52 +0100

by zoo:logic

Lots of new followers, hello :) sorry it’s boring and quiet right now, exams have taken over my life a little bit. For now, here’s a sexy pigeon I caught showing off for the gals during a revision break at the park the other day.

It is a well-known phenomenon that within mammalian species,...

Tue, 15 May 2012 13:25:17 +0100

It is a well-known phenomenon that within mammalian species, females tend to outlive males. The male sex hormone testosterone not only puts males at behavioural risk of injury in terms of aggression and competitiveness (as well as involving high energy expenditure), but also increases levels of harmful LDL cholesterol in the blood, leading to a greater risk of heart disease and stroke. As such, a broad variety of immune-related genes may be more important in males than it is in females. Researchers studying the Alpine chamois (Rupicapra rupicapra) have recently investigated this hypothesis. Observing wild chamois living in the eastern Alps, scientists discovered that in areas affected by scabies, reproductive-age males had a higher death rate than both females and younger males. They noted that mature males depleted their fat stores at the end of the winter around 6 weeks earlier than females and younger males, presumably due to the large amount of energy expended in rutting. Lower fat reserves leave less energy for maintaining a strong immune system. Researchers wanted to know whether variation in genes that influenced immune response could improve male probability of survival.

The scientists chose to examine a gene called MHC class II DRB from what is known as the major histocompatibility complex (MHC). This is a set of around 128 active genes along with 96 non-functional pseudogenes that have an important role in the immune system. The MHC shows huge variation between individuals - 100 times greater than the genome average, giving a 10% difference between any two unrelated individuals. These variations seem to correspond with differences in susceptibility to a whole host of diseases such as malaria, tuberculosis and HIV/AIDS.

In areas affected by scabies, the proportion of males that were heterozygous (had two different copies of the gene) increased with age, implying that homozygous individuals (those with two identical copies of the gene) had higher mortality rates. Male individuals heterozygous at the locus were indeed found to survive significantly longer than homozygous individuals - but this did not apply in females. The research supports the theory that when the immune system is compromised, heterozygosity in immune genes increases male chances of survival.

Ref: Schaschl H., Suchentrunk F., Morris D. L. et al., 2012. Sex-specific selection for MHC variability in Alpine chamois. BMC Evolutionary Biology 12:20 [link]
Twyman R., 2003. The major histocompatibility complex. Wellcome Trust: The Human Genome [link]

For a long time, the history of the domestication of the horse...

Thu, 10 May 2012 17:28:42 +0100

For a long time, the history of the domestication of the horse has been a muddled one. While archaeological evidence suggests that the domestic horse (Equus caballus) originated in the western Eurasian steppes (Ukraine, southwest Russia and west Kazakhstan), a large variety of female lineages in the gene pool contradicts this, implying not a single origin but instead multiple domestication events. An important unanswered question was whether the spread of horse domestication around the world involved the actual movement of herds from a specific geographic origin, known as ‘demic spread’, or whether it simply involved passing on successful techniques so that people in other regions could domesticate their own local wild horses, resulting in multiple domestication events from numerous different populations. New research that has analysed mitochondrial DNA and Y-chromosomes from a genetic database of over 300 horses has finally resolved the answers to these questions. The data has traced the origins of domestic horses to a single ancestral population of Equus ferus (now extinct) that was indeed living in the western Eurasian steppes from at least 160,000 years ago. Humans first domesticated the horse in this region around 4000 B.C., and from here domesticated horses spread outwards across Europe and Asia, in the process of which stock was supplemented with local wild horses in different regions. These wild horses that were bred into domestic herds were the source of the new female lineages that we can identify in the gene pool today.

Ref: Warmuth V., Eriksson A., Bower M. A., Barker G., Barrett E. et al., 2012. Reconstructing the origin and spread of horse domestication in the Eurasian steppe. PNAS Online [link]

so i want to study zoology and I wanted to ask if you have any advice/tips I should know for whats to come?

Tue, 08 May 2012 17:38:15 +0100

Hi, first of all good choice of subject! :) I think an important thing to remember that I didn’t necessarily consider much before I started is that zoology is a science degree, and unfortunately - however much I would like it to be - it’s not always specifically learning cool stuff about animals. I think it is quite important to have a broader interest in biology as well as just the animal side in order to tackle a zoology degree, as you’ll generally have to take units such as molecular biology and genetics that are of course important and necessary but - as they tend to be shared across the life sciences degrees - tend to be run by people that are not zoologists and do not explicitly relate the topics to animals, so they can feel a bit heavy. You’ll also have to deal with a bit of stats for analysing the results of any practical work and in reading scientific papers, as well as some mathematical models related to scientific theories. Not that I’m not trying to put you off!! - I’ve found it to be an interesting degree for the most part, but I feel that if someone had reminded me a zoology degree would not be learning cool facts about different animals all day long I’d have felt less shocked by the slightly less pleasant stuff we have to study. I’d recommend looking closely at the units offered at different universities and choose a course that sounds best suited to your interests. The units I’ve enjoyed most during my degree are the field trips, which tend to be specifically tailored towards zoology so I’d also recommend checking out what they offer in terms of trips during your degree. But what I’ve loved most about it is the wonderful people I’ve met on my course - animal people are the best! I don’t know if I’ve just been lucky but everyone on our course gets on so well and if you want to surround yourself with lovely like-minded people zoology is a great choice. Best of luck with it!

The extraordinary adaptations we can observe in every organism...

Thu, 03 May 2012 20:27:00 +0100

The extraordinary adaptations we can observe in every organism on Earth amount to an almost limitless assortment of useful things nature can teach us - and researchers from the University of Bristol are learning something particularly cool from the masters of camouflage, organisms such as the squid (order Teuthida) and zebrafish (Danio rerio). These animals use pigment-containing cells in order to mimic their surroundings, giving them rapidly adjustable natural camouflage the likes of which us as humans can only dream of. However, by creating artificial materials based on the same mechanisms seen in these organisms, we can bring it one step closer to reality.

In cephalopods such as the squid, cells called chromatophores sit immediately below the skin, filled with either yellow pigment (xanthophores), red pigment (erythrophores) or brown pigment (melanophores), and stacked vertically in that order with xanthophores uppermost. The pigment is held in small elastic sacs surrounded by 15-25 muscles, which when contracted, cause the sac to stretch to cover a larger surface area with colour; when relaxed, the pigment is contained in a tiny blob. The muscles are stimulated by nerves that are linked directly to the brain - every single cell is served by at least one nerve ending! This exquisite level of control means that highly complex patterns can be easily formed to closely match even the most variable of backgrounds.

Zebrafish use a slightly different mechanism in which a small reservoir of pigment travels up to the skin surface and spreads out in an ink-like manner when stimulated, usually by hormones rather than through the nervous system.

The researchers have made use of these mechanisms by creating artificial muscles that include smart materials that are responsive to an electric current - these are known as dielectric elastomers, or DEs. When the electric circuit is applied, the smart DEs expand; when short-circuited, they return to their original shape. In addition, a different pump-based system was produced using smart DEs that reflected the mechanism used by zebrafish. The end products can be made into a soft ‘skin’ which, with further development, could be used to make “smart clothes” that could allow us to mimic the camouflaging abilities seen in in nature.

Ref: Rossiter J., Yap B. & Conn A., 2012. Biomimetic chromatophores for camouflage and soft active surfaces. Bioinspiration & Biomimetics 7 036009 [link]
The Biomimicry Institute, 2011. Rapid color change used for protection: cuttlefish. The Biomimicry Institute [link]
Wood J. & Jackson K., 2004. How Cephalopods Change Color. The Cephalopod Page [link]

"It seems to me that the natural world is the greatest source of excitement; the greatest source of..."

Wed, 02 May 2012 10:39:25 +0100

“It seems to me that the natural world is the greatest source of excitement; the greatest source of visual beauty; the greatest source of intellectual interest. It is the greatest source of so much in life that makes life worth living.”

- Sir David Attenborough

Research using mice has revealed a new gene that plays an...

Tue, 01 May 2012 17:42:43 +0100

Research using mice has revealed a new gene that plays an essential role in mammalian fertility: the PDILT gene encodes a protein that enables sperm to navigate their way through the oviduct and bind correctly to the egg during the process of fertilisation. The PDILT protein stimulates the correct folding of another protein called ADAM3, which is then localised to the outer membrane of the sperm. Without PDILT, the ADAM3 protein is not folded correctly or transported to where it is needed to be. Its critical importance was evident following the discovery that if its expression is ‘switched off’ in sperm, fewer than 3% of eggs become fertilised, in comparison with approximately 80% when the gene is active. Sperm lacking PDILT are not only unable to bind the egg fully, but find it difficult to navigate through the oviduct to get to it in the first place. The experiments also revealed that what are known as cumulus cells, which form a protective layer around the egg, aid in effective binding of the sperm to the egg and will help to rescue the binding difficulties caused by the absence of PDILT, enabling successful fertilisation. The next step will be to examine how the gene works in humans - from there, it may be possible to produce fertility treatments that could aid in making IVF more successful for those couples that are faced with low fertility.

Ref: Durham University, 2012. Gene involved in sperm-to-egg binding is key to fertility in mammals. EurekAlert! News [link]

blinkanditsover: A mouse diced with death when it stole some...

Mon, 30 Apr 2012 20:38:33 +0100

blinkanditsover:

A mouse diced with death when it stole some food from under the nose of a leopard at the Santago Rare Leopard Project in Hertfordshire.

Instead of pouncing on the mouse, the 12-year-old African leopard, called Sheena, simply watched as it fed on scraps of meat thrown into its enclosure.

At one stage she tried to nudge the mouse away with her nose, but the mouse carried on eating regardless.