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May 10 2012

23:00

NCBI ROFL: Female chimps choose their sex noises depending on the audience.

Female chimpanzees use copulation calls flexibly to prevent social competition.

“The adaptive function of copulation calls in female primates has been debated for years. One influential idea is that copulation calls are a sexually selected trait, which enables females to advertise their receptive state to males. Male-male competition ensues and females benefit by getting better mating partners and higher quality offspring. We analysed the copulation calling behaviour of wild female chimpanzees (Pan troglodytes schweinfurthii) at Budongo Forest, Uganda, but found no support for the male-male competition hypothesis. Hormone analysis showed that the calling behaviour of copulating females was unrelated to their fertile period and likelihood of conception. Instead, females called significantly more while with high-ranking males, but suppressed their calls if high-ranking females were nearby. Copulation calling may therefore be one potential strategy employed by female chimpanzees to advertise receptivity to high-ranked males, confuse paternity and secure future support from these socially important individuals. Competition between females can be dangerously high in wild chimpanzees, and our results indicate that females use their copulation calls strategically to minimise the risks associated with such competition.”

Photo: flickr/downing.amanda

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May 03 2012

23:00

NCBI ROFL: PhDs agree: bees see like me!

Bees perceive illusory colours induced by movement.

“Certain black-and-white patterns, when rotated at appropriate speeds, can create the artificial perception of hues. We report that this illusion is not confined to human vision, but is also perceived by an insect, the honeybee. The findings suggest that certain features underlying the processing of colour information are shared by man and bee.”


Bonus quotes from the main text:

Freely-flying bees (Apis melrifera) were trained to discriminate between two visual stimuli presented in a horizontal plane immediately beneath the surface of a glass-topped table. One of the stimuli bore a reward of sugar water. The locations of the stimuli were interchanged frequently to prevent the bees from using position cues to identify the rewarded stimulus.

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May 02 2012

23:00

NCBI ROFL: The identification of attractive volatiles in aged male mouse urine.

“In many species, older males are often preferred mates because they carry “good” genes that account for their viability. In some animals, including mice, which rely heavily on chemical communication, there is some indication that an animal’s age can be determined by its scent. In order to identify the attractants in aged male mouse urine, chemical and behavioral studies were performed. We herein show that aged mice have higher levels of 3,4-dehydro-exo- brevicomin (DB), 2-sec-butyl-4,5-dihydrothiazole (BT), and 2-isopropyl-4,5-dihydrothiazole (IT) and a lower level of 6-hydroxy-6-methyl-3-heptanone relative to adult male mice. We also demonstrate that the attraction of females to the odor of male mouse urine is greater when the urine is from aged males. However, the attraction of aged urine odor was offset by the ultrafiltration of adult and aged mouse urine. When DB, BT, and IT were added to adult urine, the attraction of the urine was enhanced. Our results suggest that inbred aged male mice develop an aging odor that is attractive to female mice in an experimental setting and that this attraction is due to increased mouse pheromone signaling.”


April 25 2012

23:00

NCBI ROFL: Wish you could get drunk without blacking out? Next time, have a coffee.

Alcohol-induced retrograde memory impairment in rats: prevention by caffeine.

“RATIONALE:
Ethanol and caffeine are two of the most widely consumed drugs in the world, often used in the same setting. Animal models may help to understand the conditions under which incidental memories formed just before ethanol intoxication might be lost or become difficult to retrieve.
OBJECTIVES:
Ethanol-induced retrograde amnesia was investigated using a new odor-recognition test.
MATERIALS AND METHODS:
Rats thoroughly explored a wood bead taken from the cage of another rat, and habituated to this novel odor (N1) over three trials. Immediately following habituation, rats received saline, 25 mg/kg pentylenetetrazol (a seizure-producing agent known to cause retrograde amnesia) to validate the test, 1.0 g/kg ethanol, or 3.0 g/kg ethanol. The next day, they were presented again with N1 and also a bead from a new rat’s cage (N2).
RESULTS:
Rats receiving saline or the lower dose of ethanol showed overnight memory for N1, indicated by preferential exploration of N2 over N1. Rats receiving pentylenetetrazol or the higher dose of ethanol appeared not to remember N1, in that they showed equal exploration of N1 and N2. Caffeine (5 mg/kg), delivered either ...


April 09 2012

23:00

NCBI ROFL: The role of pet dogs in casual conversations of elderly adults.

“Casual conversations were recorded as elderly persons routinely walked their dogs through a familiar mobile home park in the United States. Control observations included walks without dogs by owners and non-owners of dogs. All owners talked to and about their dogs. Transcribed conversations indicated that dogs were a primary focus of conversation. A majority of sentences to dogs were imperatives; the owners were instructing the dogs. Dog owners frequently included dogs’ names or nicknames in their sentences when they spoke to the dogs and made reference to the dogs’ wishes or needs. Speaking to dogs was also associated with frequent repetition of sentences. Passersby talked to the owners about their dogs whether or not the dogs were present. When dog owners spoke with other people, their conversations often concerned activities that were occurring in the present, whereas conversations of non-owners focused on stories about past events. Dog owners reported taking twice as many daily walks as non-owners. Dog owners also reported significantly less dissatisfaction with their social, physical and emotional states.”

Photo: flickr/podoboq

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April 06 2012

23:00

NCBI ROFL: Female cockroaches avoid slutty males.

Female mate preference and sexual conflict: females prefer males that have had fewer consorts.

“Different aspects of male quality as a mate can vary independently. When this is the case, females may need to use multiple cues to accurately assess overall mate quality. We examined the pattern of mating preference in the cockroach Nauphoeta cinerea. Sexual conflict occurs in this species because male manipulation of female mating receptivity can result in reduced female fitness. We predicted that since females cannot remate within a single reproductive bout because of male manipulation, females should assess male mating history to avoid mating with males with low fertility caused by sperm exhaustion. In a mate-preference experiment, we found that females discriminated against males who had mated multiple times. Females also discriminated against males who had consorted with several females but had been prevented from mating with those females. Thus, females appeared to be able to detect cues on males that were derived from previous mates and to use this information to avoid mating with sperm-exhausted males. We suggest that females may commonly use multiple cues to assess different aspects of mate quality, especially when male ...


March 09 2012

00:00

NCBI ROFL: On the explosion of carcasses.

Float, explode or sink: postmortem fate of lung-breathing marine vertebrates

“What happens after the death of a marine tetrapod in seawater? Palaeontologists and neontologists have claimed that large lung-breathing marine tetrapods such as ichthyosaurs had a lower density than seawater, implying that their carcasses floated at the surface after death and sank subsequently after leakage of putrefaction gases (or ‘‘carcass explosions’’). Such explosions would thus account for the skeletal disarticulation observed frequently in the fossil record. We examined the taphonomy and sedimentary environment of numerous ichthyosaur skeletons and compared them to living marine tetrapods, principally cetaceans, and measured abdominal pressures in human carcasses. Our data and a review of the literature demonstrate that carcasses sink and do not explode (and spread skeletal elements). We argue that the normally slightly negatively buoyant carcasses of ichthyosaurs would have sunk to the sea floor and risen to the surface only when they remained in shallow water above a certain temperature and at a low scavenging rate. Once surfaced, prolonged floating may have occurred and a carcass have decomposed gradually. Our conclusions are of significance to the understanding ...


March 02 2012

00:00

NCBI ROFL: Chimpanzees deceive a human competitor by hiding.

“There is little experimental evidence that any non-human species is capable of purposefully attempting to manipulate the psychological states of others deceptively (e.g., manipulating what another sees). We show here that chimpanzees, one of humans’ two closest primate relatives, sometimes attempt to actively conceal things from others. Specifically, when competing with a human in three novel tests, eight chimpanzees, from their first trials, chose to approach a contested food item via a route hidden from the human’s view (sometimes using a circuitous path to do so). These findings not only corroborate previous work showing that chimpanzees know what others can and cannot see, but also suggest that when competing for food chimpanzees are skillful at manipulating, to their own advantage, whether others can or cannot see them.”

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Photo: flickr/Tambako the Jaguar

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February 29 2012

00:00

NCBI ROFL: It was as big as my head, I swear! Biased spider size estimation in spider phobia.

“The current study tested the association between fear and perception in spider phobic individuals (n=57) within the context of a treatment outcome study. Participants completed 5 post-treatment Behavioral Approach Tasks (BATs) in which they encountered a live spider and were asked to provide spider size estimates. Consistent with predictions, results indicated that high levels of fear were associated with magnified perception of phobic stimuli. Specifically, we found a significant positive correlation between size estimates and self-reported fear while encountering spiders. Together with previous findings, these results further support the notion that fear is involved in the encoding and processing of perceptual information.”

Thanks to @NatRevMicro for today’s ROFL!
Photo: flickr/pamlau

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February 28 2012

00:00

NCBI ROFL: Probing pooch paw preferences.

Effect of use on the elective appearance of an instrumental reaction in dogs.

“Dogs were used to elaborate two instrumental reactions flexing the left or right forepaw respectively to pull a dish of food within reach of its mouth. If both paws were simultaneously fixed to levers, dog was faced with a choice between two reactions. In preliminary trials right paw preference was strong despite equal effectiveness of the left paw in obtaining the food. The aim of the experiment was to alter this right paw preference by forcing the use of the left paw. Each ten training trials were followed by a test with free choice of paws. According to the probabilities PL = 0.8 and PR = 0.2, a random table was used to determine the order of forced use of the right or left paw. In all, 1,000 training trials and 100 tests with free choice were carried out on each of three dogs. According to the training program in every 100 training trials the left paw was made to display the reaction a total 80 times, the right paw, 20 times. Absolute alteration in the preference occurred even though in ...


February 14 2012

00:00

NCBI ROFL: A micro creeping robot for colonoscopy based on the earthworm.

“Minimally Invasive Surgery (MIS) has become one of the most important research areas in the field of medical engineering. Robotic colonoscopy is a typical medical procedure that complies with the requirements of MIS. In this paper, a new novel miniature robot for intestinal inspection based on the earthworm is described; its diameter and length are 7.5 mm and 120 mm respectively. The micro robot is driven by a DC motor which has good performance and sufficient power. In this paper the structure and locomotion mechanism of this robot are introduced; the mechanical model is built; and simulation is carried out. The control system and software design are also discussed in detail. Some actuating characteristic experiments have been performed, where the micro robot creeps in declining rubber tubes. The experimental results are in accord with simulation results, and show that this kind of robot can move reliably in horizontal and certain declining tubes. This research has laid a foundation for the application of the miniature robot endoscope.”

Bonus figure:

Photo: flickr/pfly

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February 09 2012

00:00

NCBI ROFL: My research involves watching pigs poop out balloons…hey, why are you running away?

The effect of feeding on defecation behaviour in pigs.

“The effect of eating on defecation behaviour was investigated in four 20-30 kg pigs. Rectal distention stimulation was performed pre- and postprandially at 10 cm from the anus with a 5 cm latex balloon. Volume was increased in steps of 10 ml up to 200 ml of air or until balloon defecation. Dependent measures were volume, rectal pressure, determined with a solid state pressure transducer inside the balloon probe, rectal compliance, and an index of distention induced contractile activity. The volume and pressure required to elicit defecation was significantly lower after feeding (p less than 0.01). Distention induced contractile activity was significantly increased near defecation threshold, but pre- and postprandial conditions were not different. There was no difference in rectal compliance pre- and postprandially. These results suggest that eating lowers defecation threshold in terms of distention volume and rectal pressure, and that these changes are not dependent on altered rectal compliance or changes in distention induced motor activity.”

Photo: flickr/ArtBrom

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February 08 2012

00:00

NCBI ROFL: How dogs navigate to catch frisbees.

“Using micro-video cameras attached to the heads of 2 dogs, we examined their optical behavior while catching Frisbees. Our findings reveal that dogs use the same viewer-based navigational heuristics previously found with baseball players (i.e., maintaining the target along a linear optical trajectory, LOT, with optical speed constancy). On trials in which the Frisbee dramatically changed direction, the dog maintained an LOT with speed constancy until it apparently could no longer do so and then simply established a new LOT and optical speed until interception. This work demonstrates the use of simple control mechanisms that utilize invariant geometric properties to accomplish interceptive tasks. It confirms a common interception strategy that extends both across species and to complex target trajectories.”

Photo: Flickr/ giustina_ilyusha

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January 11 2012

23:35

NCBI ROFL: Do dogs really have a “guilty look”?

Disambiguating the “guilty look”: salient prompts to a familiar dog behaviour.

“Anthropomorphisms are regularly used by owners in describing their dogs. Of interest is whether attributions of understanding and emotions to dogs are sound, or are unwarranted applications of human psychological terms to non-humans. One attribution commonly made to dogs is that the “guilty look” shows that dogs feel guilt at doing a disallowed action. In the current study, this anthropomorphism is empirically tested. The behaviours of 14 domestic dogs (Canis familiaris) were videotaped over a series of trials and analyzed for elements that correspond to an owner-identified “guilty look.” Trials varied the opportunity for dogs to disobey an owner’s command not to eat a desirable treat while the owner was out of the room, and varied the owners’ knowledge of what their dogs did in their absence. The results revealed no difference in behaviours associated with the guilty look. By contrast, more such behaviours were seen in trials when owners scolded their dogs. The effect of scolding was more pronounced when the dogs were obedient, not disobedient. These results indicate that a better description of the so-called guilty look is that it is a response to ...


December 15 2011

00:10

NCBI ROFL: Chest waxers beware: body hair protects against bedbugs.

Human fine body hair enhances ectoparasite detection

“Although we are relatively naked in comparison with other primates, the human body is covered in a layer of fine hair (vellus and terminal hair) at a relatively high follicular density. There are relatively few explanations for the evolutionary maintenance of this type of human hair. Here, we experimentally test the hypothesis that human fine body hair plays a defensive function against ectoparasites (bed bugs). Our results show that fine body hair enhances the detection of ectoparasites through the combined effects of (i) increasing the parasite’s search time and (ii) enhancing its detection.”

Bonus excerpt from the full text:

“(c) Experimental treatment
The experimental procedure required that each host was tested on a shaved and unshaved arm (randomized with respect to arm and temporal sequence). The treatment arm was shaved on the upper surface between the wrist and the elbow with a new razor (Gillette Mach 4), while using the same brand of perfume- and colour-free soap (Simple). A rectangle measuring 5 × 10 cm was then drawn on the shaved area with a marker pen and vaseline (a barrier to bed bug locomotion) applied to the marked boundary. This ensured each ...


December 09 2011

23:46

NCBI ROFL: Does bestiality cause penile cancer?

Sex with Animals (SWA): Behavioral Characteristics and Possible Association with Penile Cancer. A Multicenter Study

“Introduction.  Zoophilia has been known for a long time but, underreported in the medical literature, is likely a risk factor for human urological diseases. Aim.  To investigate the behavioral characteristics of sex with animals (SWA) and its associations with penile cancer (PC) in a case-control study. Methods.  A questionnaire about personal and sexual habits was completed in interviews of 118 PC patients and 374 controls (healthy men) recruited between 2009 and 2010 from 16 urology and oncology centers. Main Outcome Measures.  SWA rates, geographic distribution, duration, frequency, animals involved, and behavioral habits were investigated and used to estimate the odds of SWA as a PC risk factor. Results.  SWA was reported by 171 (34.8%) subjects, 44.9% of PC patients and 31.6% of controls (P < 0.008). The mean ages at first and last SWA episode were 13.5 years (standard deviation [SD] 4.4 years) and 17.1 years (SD 5.3 years), respectively. Subjects who reported SWA also reported more venereal diseases (P < 0.001) and sex with prostitutes (P < 0.001), and were more likely to have had more than 10 lifetime sexual partners (P < 0.001) than those who ...


December 06 2011

00:46

NCBI ROFL: Think all wasps look alike? Then clearly you’re not a wasp.

Specialized face learning is associated with individual recognition in paper wasps.

“We demonstrate that the evolution of facial recognition in wasps is associated with specialized face-learning abilities. Polistes fuscatus can differentiate among normal wasp face images more rapidly and accurately than nonface images or manipulated faces. A close relative lacking facial recognition, Polistes metricus, however, lacks specialized face learning. Similar specializations for face learning are found in primates and other mammals, although P. fuscatus represents an independent evolution of specialization. Convergence toward face specialization in distant taxa as well as divergence among closely related taxa with different recognition behavior suggests that specialized cognition is surprisingly labile and may be adaptively shaped by species-specific selective pressures such as face recognition.”

Bonus Figure:

“Images used for training wasps. Wasps were trained to discriminate between pairs of images. Pairs are shown in the same row except for P. metricus face images. For P. metricus face images, the unmanipulated faces in the top row were paired with the manipulated images of the other face (for example, top left paired with middle left and bottom left).”

Photo: Flickr/quinet

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November 15 2011

23:57

November 12 2011

00:14

NCBI ROFL: A scientific analysis of 400 YouTube videos of dogs chasing their tails.

A Vicious Cycle: A Cross-Sectional Study of Canine Tail-Chasing and Human Responses to It, Using a Free Video-Sharing Website
Figure 1. Screenshot of a video of a Golden Retriever chasing its tail on YouTube™.

“Tail-chasing is widely celebrated as normal canine behaviour in cultural references. However, all previous scientific studies of tail-chasing or ‘spinning’ have comprised small clinical populations of dogs with neurological, compulsive or other pathological conditions; most were ultimately euthanased. Thus, there is great disparity between scientific and public information on tail-chasing. I gathered data on the first large (n = 400), non-clinical tail-chasing population, made possible through a vast, free, online video repository, YouTube™. The demographics of this online population are described and discussed. Approximately one third of tail-chasing dogs showed clinical signs, including habitual (daily or ‘all the time’) or perseverative (difficult to distract) performance of the behaviour. These signs were observed across diverse breeds. Clinical signs appeared virtually unrecognised by the video owners and commenting viewers; laughter was recorded in 55% of videos, encouragement in 43%, and the commonest viewer descriptors were that the behaviour was ‘funny’ (46%) or ‘cute’ (42%). Habitual tail-chasers had 6.5+/−2.3 times the odds of being described as ‘Stupid’ than other dogs, and perseverative dogs were 6.8+/−2.1 times more frequently described as ‘Funny’ than distractible ones were. Compared with breed- and age-matched control videos, tail-chasing videos were significantly more often indoors and with a computer/television screen switched on. These findings highlight that tail-chasing is sometimes pathological, but can remain untreated, or even be encouraged, because of an assumption that it is ‘normal’ dog behaviour. The enormous viewing figures that YouTube™ attracts (mean+/−s.e. = 863+/−197 viewings per tail-chasing video) suggest that this perception will be further reinforced, without effective intervention.”

Bonus Table:

Table 2. Human encouragement and responses to tail-chasing in dogs on YouTube™.

 

Thanks to @InkfishEP for today’s ROFL!

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November 03 2011

22:38

NCBI ROFL: The physics of penguin huddling.

Coordinated movements prevent jamming in an Emperor penguin huddle.

“For Emperor penguins (Aptenodytes forsteri), huddling is the key to survival during the Antarctic winter. Penguins in a huddle are packed so tightly that individual movements become impossible, reminiscent of a jamming transition in compacted colloids. It is crucial, however, that the huddle structure is continuously reorganized to give each penguin a chance to spend sufficient time inside the huddle, compared with time spent on the periphery. Here we show that Emperor penguins move collectively in a highly coordinated manner to ensure mobility while at the same time keeping the huddle packed. Every 30-60 seconds, all penguins make small steps that travel as a wave through the entire huddle. Over time, these small movements lead to large-scale reorganization of the huddle. Our data show that the dynamics of penguin huddling is governed by intermittency and approach to kinetic arrest in striking analogy with inert non-equilibrium systems, including soft glasses and colloids.”

Bonus quote from the Discussion in the full text:

“In addition, huddle movements allow separate smaller huddles to merge into larger clusters. Such merging is analogous to the merging of magnetic domains as the thermodynamic temperature is decreased towards the Curie point, the temperature above which a magnet loses its magnetism, or analogous to a phase transition in a disordered material that is brought towards a critical point. This is an essential process in condensed matter physics, penguins included.”

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