Does shooting birds make them smarter?

Human hunters may be making birds smarter by inadvertently shooting those with smaller brains. That’s the conclusion of a new study, which finds that hunting may be exerting a powerful evolutionary force on bird populations in Denmark, and likely wherever birds are hunted. But the work also raises a red flag for some researchers who question whether the evolution of brain size can ever be tied to a single factor.

The new work “broadens an emerging view that smarts really do matter in the natural, and increasingly human-dominated, world,” says John Marzluff, a wildlife biologist and expert on crow cognition at the University of Washington in Seattle who was not involved with the work.

Hunting and fishing are known to affect many animal populations. For instance, the pike-perch in the Finnish Archipelago Sea has become smaller over time thanks to fishing, which typically removes the largest individuals from a population. This pressure also causes fish to reach sexual maturity earlier. On land, natural predators like arctic foxes and polar bears can also drive their prey species to become smarter because predators are most likely to catch those with smaller brains. For instance, a recent study showed that common eiders (maritime ducks) that raise the most chicks also have the largest heads and are better at forming protective neighborhood alliances than ducks with smaller heads—and presumably, brains.

Does the same hold true for birds that dodge human hunters? To find out, Anders Pape Møller, an evolutionary biologist at the University of Paris-Sud, assessed the brain sizes of 3781 birds from 197 species brought to taxidermists in Denmark between 1960 and 2015. The birds included pheasants, partridges, wood grouse, magpies, and hooded crows. Danish law requires taxidermists to record the date and cause of death of every specimen they handle. Møller’s co-author, Johannes Erritzøe, a taxidermist and ornithologist at the House of Bird Research in Christiansfeld, Denmark, autopsied each bird, noted its mass, and weighed its extracted brain. The scientists also assessed the birds’ body condition and age at death.

They found that 299, or 7.9%, of the 3781 birds were shot. Birds with smaller brains relative to their body size were shot more often, as were larger individuals (which offer a bigger target), and males (perhaps because of their brighter colors). But if a bird had a large brain relative to its body size, the probability that it would be shot decreased nearly 30-fold, the scientists report today in Biology Letters. This held true, regardless of the birds’ health, body mass, sex, and species. Hunters, they conclude, are unwittingly turning their prey into large-brained birds by eliminating those with pea-sized brains from the population.

The  scientists also compared the birds' other internal organs--heart, liver, lungs--and found that only the brain was smaller in the hunted birds. “It means that hunting has a very peculiar and specific effect on the brain and not the other bodily functions of these animals,” Møller says.

Hunters aren’t specifically targeting the smaller-brained birds, he adds. Such birds simply aren’t savvy about hunters, apparently lacking the smarts to realize that people with guns are dangerous. “They take longer to fly when approached by someone with a gun, whereas larger-brained birds enjoy the benefit of being wary.” Moller and his team couldn’t track changes in brain size over time, since hunting regulations in many of the study areas have shifted; there are some areas where it was once allowed, but it’s now banned. That could let birds with smaller brains gradually make up a larger part of the population, Møller predicts.

“The study is intriguing, but I will remain a bit sceptical because it is based on a comparative long-term data set and not an experiment,” says Jesper Madsen, a population ecologist at Aarhaus University in Rønde, Denmark, who was not involved in the study. “To conclude that hunting selects for larger brains requires more than a correlational study.”

Such an experiment is already underway—albeit inadvertently, Møller says. In the last 5 years, the hunting of snipe and curlew has been banned permanently in Europe. Scientists could compare specimens from the earlier hunting period with those collected after the ban to see if these birds are evolving smaller brains, Møller says. “That’s a predictable consequence of stopping hunting.”

Still, Madsen isn’t alone in his scepticism. “My heart drops every time I see another study like this showing a correlation between some factor and brain size,” says Susan Healy, an evolutionary biologist at the University of St. Andrews in the United Kingdom. In 2007, she and Candy Rowe, a behavioral ecologist at Newcastle University in the United Kingdom, assessed more than 50 studies that revealed a correlation between brain size and behavioral traits such as migration, deception, and female promiscuity. They concluded that this type of research did little to advance an understanding of either brain evolution or function.

Healy’s and Madsen’s concerns are valid, Marzluff says. But, he adds, the study is valuable because of the questions it raises. “For example, did smarts pay off more for some species than for others? Were similar trends seen in social versus solitary species? That’s what correlational studies do: They generate questions.”

Indeed, the authors raise several at the end of their study. To wit: If hunters are indeed making birds smarter, what will this do long-term to bird populations and to the sport of hunting itself? Will these birds be increasingly harder to catch, for example? And how would this affect wild predators that live on these species? Møller predicts they’ll have a harder time. As for the answer, stay tuned.

Rare White Giraffe and Other Unusually Pale Animals

Albino and leucistic animals abound in the animal kingdom, from squirrels to crayfish.

Omo, the rare white calf recently spotted in Tanzania’s Tarangire National Park, is one special snowflake.

But unusually white animals in other species—from eagles to bears to crayfish—are often seen in nature. There are three ways this can occur: albinism, leucism, and isabellinism.

True albinos are unable to produce any kind of pigment, hence their white coloration and pink eyes: Blood vessels normally masked by eye color show through. (See "Special Albinos and Unusually White Animals.")

Albinism is a recessive trait, meaning both parents must pass the mutation on to their offspring. Snowflake, an albino lowland gorilla, had parents that passed on copies of a gene found in other albino animals like mice, horses, and chickens.

Leucistic animals are mostly white but can produce some pigment. For example, many still sport color in their eyes. Two white spider monkeys recently spotted in a Colombian rain forest likely have this condition.

A third condition is called isabellinism, in which a genetic mutation leaches the color out of pigmented penguin feathers. Animals that have isabellinism are different from albino animals because they can still produce pigment.

Leucistic and isabelline are sometimes used interchangeably to describe the pale brown or "blonde" coloration of penguins with this condition.

Keep clicking to see our roundup of albinos and other white animals.

Nova Scotia man banned from owning animals for life

A Nova Scotia man has been banned from owning pets for life after pleading guilty under the Animal Protection Act this week.

On January 19, 2016, the SPCA received a complaint that alleged multiple dogs were tethered outside without adequate shelter at a property in Kings County, N.S.

Three dogs were located – all were emaciated, anemic, severely matted and in extremely poor condition. One was found frozen to the ground by its chain and unable to stand.

The three dogs underwent extensive veterinarian care and were successfully rehabilitated and adopted.

Thursday, Leroy Marshall pleaded guilty to a charge of causing an animal to be in distress under the Animal Protection Act and was handed a lifetime ban on owning companion animals.

Why Do We Love Some Animals But Eat Others?

Attitudes toward animals are a delicate and complicated matter.

We can group animals into vertebrates and invertebrates, into the wild and the domestic — or into those we keep as pets, those we eat and those we regard with disgust as vermin.

It's okay to love them — but only so much.

And there's the question of what types of animals you can love. You're allowed to love a dog or a cat. But can you, should you, is it appropriate, to love other kinds of animals? My brother had a hermit crab when he was a boy. I don't know how he felt about it — but can a healthy, well-rounded person love a hermit crab?

I'm not passing judgment. It strikes me that the shifting, unstable, historical, emotional, playful and earnest feelings we Americans have about animals has a lot to do with other kinds of value, meaning and quality in our lives.

And, so, it is with a real sense of curiosity that I wonder about our varying relationships with animals. Why, for example, it is that we do not even notice road kill, for the most part — let alone stop to mourn it? And what can be said about the fact that the sale of bull semen is a big part of the cattle industry — and the methods used to create supply?

You can get the salacious details in Jane C. Desmond's fascinating new book Displaying Death and Animating Life: Human-Animal Relations in Art, Science and Everyday Life. This is a scholarly work devoted to looking at the variety and tensions surrounding human-animal relations in, as the subtitle puts it, art, science and everyday life. Her focus, in this gripping book, is our contemporary American society (to the extent that there is any such a unified thing).

She investigates, for example, our pet burial practices and the ways in which these are similar to but also so very different from those surrounding human burial. Perhaps precisely because there is, or continues to be, as it happens, something marginal, ridiculous or even outrageous about the very idea of a pet cemetery, these have become, she shows, places for creative and improvisatory engagement with death and mourning. Only a very small fraction of the millions and millions of American pet owners bury their deceased pets in designated pet graveyards. She makes a good case, though, that such burial practices — she also explores the writing of pet obituaries — help us understand shifting conceptions of family and kinship.

Of particular interest to this reader is Desmond's level-headed treatment of the phenomenon of "art" by animals. Desmond is careful to tease out the many different sorts of factors lurking behind what is no doubt a growing market. She recounts the sale of three paintings — by an ape — that fetched $30,000 at a London auction house in 2005.

Students of animal cognition and human evolution, as well as those interested in raising funds for zoos and other animal-oriented philanthropies, all have a vested interest in the production and study of so-called animal art.

But do animals really make art?

Art, as we know it in the human world, happens against the background of shared culture. We use the term"outsider" art to refer to paintings, buildings, quilts, etc., by people lacking the usual training and career formation of professional artists. But the idea of art that is truly outside culture — as an animal art would have to be — is a nonstarter. It would be like imagining that animals in nature might make touchdowns. You need football — a whole practice — to get touchdowns.

Unless of course, as Desmond considers, there are animals that are not, or not entirely, outside culture because, as in the case of some chimpanzees and other nonhuman primates, they have been raised with humans and so are, in a genuine sense, at home in a bi-species environment.

Desmond notes the political meanings that may be attached to the question of animal art. If an ape is, or even might be, an artist, she considers, this could be taken to have a bearing on what sort of political obligations we have to them. When people purchase a painting by a chimpanzee to put on their wall, they may be motivated, as Desmond puts it, by the ideal (or perhaps the fantasy) of subverting the presumed primacy of the human.

She may be right about this. But I would hope that we don't make the mistake of holding the moral standing of nonhuman lives hostage to their status as would-be artists and writers. For their sake, I mean.

This is an important and moving book. Reading it is a bit like catching an unexpected glimpse of yourself in a reflection and being worried about what you see. How is it that we remain, as a culture, so largely unreflective about animals and their place in our lives?

Top 10 Longest Living Critters

More than a dozen animals live longer than we do. A new study estimates that at least one Greenland shark lived about 392 years, making it the longest-living animal with a backbone.

Here are the animals that the scientific longevity database AnAge says have lived the longest. Many of these live in the cold and in water.

The longest-living human reached 122.5 years.

1. Hexactinellid sponge: One of these Antarctic sponges lived for an estimated 15,000 years.

2. Epibenthic sponge: Another Antarctic sponge that is generally estimated to live 1,550 years.

3. Ocean quahog: This clam, nicknamed "Ming," had its rings measured and it had lived 507 years.

4. Greenland shark: A new study estimates the age of one of these sharks at 392, but it could have been somewhere between 512 and 272 years old when it died.

5. Bowhead whale: One male bowhead living in the Arctic waters was estimated to be 211 years old when it died.

6. Rougheye rockfish: These red fish of the North Pacific have lived to be 205 years old and show little effects of aging in life.

7. Red sea urchin: The spiny critters also don't seem to age much and are estimated to live about 200 years.

8. Galapagos tortoise: These slow moving creatures seen by Charles Darwin have lived as long as 177 years.

9. Shortraker rockfish: These orange-pink fish have lived up to 157 years.

10. Aldabra tortoise and Lake sturgeon: A tortoise that died at a zoo was 152 years old; unconfirmed reports put some of these tortoises living up to 180 years. One lake sturgeon, a bottom-feeder fish, is reported to have lived to be 152.

Internally coupled ears enable directional hearing in animals

Humans use the time delay between the arrival of a sound wave at each ear to discern the direction of the source. In frogs, lizards and birds the distance between the ears is too small. However, they have a cavity connecting the eardrums, in which internal and external sound waves are superimposed. Using a universal mathematical model, researchers at the Technical University of Munich (TUM) have now for the first time shown how new signals are created in this "inner ear" used by animals for localizing sounds.


A model for 15,000 species

Now, scientists working led by Leo van Hemmen, Professor of Theoretical Biophysics at the Technical University of Munich (TUM) have for the first time developed an universal mathematical model that describes how sound waves propagate through the internally coupled ears and which clues for localizing sound sources are created in the process.
"Our model is applicable to all animals with this kind of hearing system, regardless that the cavities between the eardrums of the various species look very different," explains van Hemmen. "We now understand what exactly happens inside the ears of these animals and can both explain and predict the results of experiments in all sorts of animals." Over 15,000 species have internally coupled ears - that is more than half of all land-dwelling vertebrate animals.

External and internal signals in concert

Using their model, van Hemmen and his team discovered that the animals have even developed two different methods of hearing with internally coupled ears. They occur in different frequency domains and augment each other.
In sounds below the fundamental frequency of the eardrum the time difference in the superposition of the internal and external signals is amplified up to five-fold. That is sufficient to facilitate sound localization.
In higher frequencies the time difference can no longer be evaluated. Here, another property of the signal becomes relevant: The difference in the amplitude, i.e. the loudness, of the sound perceived by the ears. "The amplitude difference occurs solely through the coupling of the two ears," explains van Hemmen. "That was a surprising result."