Posts about animals

Parasite Evolved from Cnidarians (Jellyfish etc.)

This is another instance of science research providing us interesting details about the very odd ways life has evolved on earth.

Genome sequencing confirms that myxozoans, a diverse group of microscopic parasites that infect invertebrate and vertebrate hosts, are actually highly reduced cnidarians — the phylum that includes jellyfish, corals and sea anemones.

“This is a remarkable case of extreme degeneration of an animal body plan,” said Paulyn Cartwright, associate professor of ecology and evolutionary biology at the University of Kansas (KU) and principal investigator on the research project. “First, we confirmed they’re cnidarians. Now we need to investigate how they got to be that way.”

images of myxozoans parasite spores and a jellyfish

Not only has the parasitic micro jellyfish evolved a stripped-down body plan of just a few cells, but via data generated at the KU Medical Center’s Genome Sequencing Facility researchers also found the myxozoan genome was drastically simplified.

“These were 20 to 40 times smaller than average jellyfish genomes,” Cartwright said. “It’s one of the smallest animal genomes ever reported. It only has about 20 million base pairs, whereas the average Cnidarian has over 300 million. These are tiny little genomes by comparison.”

Despite its radical phasedown of the modern jellyfish’s body structure and genome over millions of years, Myxozoa has retained the essential characteristic of the jellyfish — its stinger, or “nematocyst” — along with the genes needed to make it.

“Because they’re so weird, it’s difficult to imagine they were jellyfish,” she said. “They don’t have a mouth or a gut. They have just a few cells. But then they have this complex structure that looks just like stinging cell of cnidarian. Jellyfish tentacles are loaded with them — little firing weapons.”

The findings are the stuff of scientific fascination but also could have a commercial effect. Myxozoa commonly plague commercial fish stock such as trout and salmon.

“They’re a very diverse group of parasites, and some have been well-studied because they infect fish and can wreak havoc in aquaculture of economic importance,” Cartwright said.

Continue reading

Backyard Wildlife: Blue Jay

photo of a blue jay with a berry in its beak

Blue Jay in Arlington, Virginia (in my backyard). See more of my photos.

This is a picture I simply could not have taken before I bought my new camera (a Canon PowerShot SX60 HS Digital Camera with 65 times optical zoom). Birds are still hard to photograph but now at least occasionally I get a decent photo of birds. If you want to get photos of wildlife it is a great camera. And it is a wonderful camera in general.

I like just planting things that will feed and shelter birds (and others) rather than filling bird feeders myself. There is information on how to use your backyard to promote wildlife. I see many birds flying around in my backyard, which is quite nice. Blue jays are some of my favorites.

Blue jays diet is composed mostly of insects and nuts. They especially like acorns.

Young jays may be more likely to migrate than adults, but many adults also migrate. Some individual jays migrate south one year, stay north the next winter, and then migrate south again the next year. No one has worked out why they migrate when they do.

The pigment in blue jay feathers is melanin, which is brown. The blue color is caused by scattering light through modified cells on the surface of the feather barbs.

Related: Backyard Wildlife: Robins Attack Holly TreeBackyard Wildlife: BirdsBackyard Wildlife: CrowsBackyard Wildlife: FoxBackyard Wildlife: Chimpmunk

Cancer Rates Consistent Across Species Instead of Increasing Due to Body Mass

It would seem sensible to think cancer should be more prevalent in species with a huge number of cells, and thus more cells to become cancerous. But cancer risk doesn’t increase in this way. This interesting, open source paper, sheds some light on what is behind this.

Solutions to Peto’s paradox revealed by mathematical modelling and cross-species cancer gene analysis

Whales have 1000-fold more cells than humans and mice have 1000-fold fewer; however, cancer risk across species does not increase with the number of somatic cells and the lifespan of the organism. This observation is known as Peto’s paradox. How much would evolution have to change the parameters of somatic evolution in order to equalize the cancer risk between species that differ by orders of magnitude in size? Analysis of previously published models of colorectal cancer suggests that a two- to three-fold decrease in the mutation rate or stem cell division rate is enough to reduce a whale’s cancer risk to that of a human. Similarly, the addition of one to two required tumour-suppressor gene mutations would also be sufficient.

We surveyed mammalian genomes and did not find a positive correlation of tumour-suppressor genes with increasing body mass and longevity. However, we found evidence of the amplification of TP53 in elephants, MAL in horses and FBXO31 in microbats, which might explain Peto’s paradox in those species. Exploring parameters that evolution may have fine-tuned in large, long-lived organisms will help guide future experiments to reveal the underlying biology responsible for Peto’s paradox and guide cancer prevention in humans.

Elephants in Kenya

Elephants in Kenya by John Hunter. See more photos from my trip to Kenya.

In another way it would make sense that large animals would have hugely increased risks of cancer. As they evolved, extremely high cancer rates would be a much bigger problem for them. Therefore it wouldn’t be surprising to find they have evolved a way of reducing cancer risks.

Despite these limitations, we found genes that have been dramatically amplified in specific mammalian genomes, the most interesting of which is the discovery of 12 TP53 copies in the genome of the African elephant. We subsequently cloned those genes and identified 19 distinct copies of TP53 in African elephants and 15–20 in Asian elephants [1]. Another potential lead for solving Peto’s paradox is MAL, which is found to have eight copies in the horse genome and two in microbat. This could be an example of convergent evolution where a large animal (horse) and a small, long-lived animal (microbat) both evolved extra copies of the same gene to overcome their increased risk of cancer. Further analysis and experimentation would need to be performed to determine the function of these copies and whether or not they provide enhanced suppression of carcinogenesis.

The researchers have found an interesting potential explanation for how that has been accomplished.

Related: The Only Known Cancerless Animal (the naked mole rat)Webcast of a T-cell Killing a Cancerous CellResearchers Find Switch That Allows Cancer Cells to SpreadCancer Vaccines

Backyard Wildlife: Deer

deer in woods

Deer in backyard by John Hunter – see more of my nature photos

Deer populations have been exploding across the USA in the last century. Before that deer populations had collapsed largely due to hunting. In the last 10 or 20 years populations of deer have been largely stable (though varying quite a bit by area).

The deer populations had increased (many predators were largely wiped out and with a dramatic decline in hunter) so much that more and more complaints were being made to local governments of problems with deer grazing on property and damaging cars when the cars hit deer crossing the road.

My neighborhood is urban and I have never seen deer in the neighborhood. About 5 blocks away there is a bike path with a tree lined strip of nature where I have very occasionally seen deer. The deer in the photos I imagine got here from that strip of habitat. There is a small area (next to a school which has trees that wouldn’t be so bad for a deer for 1 night). I figured the deer would leave.

But a few days later I saw new evidence of a deer eating some small trees in my backyard – though I wasn’t sure if I missed it before. Then a couple nights later I saw a deer grazing after dark in my backyard.

I have posted about other interesting wildlife in this backyard previously: Backyard Wildlife: Fox and Backyard Wildlife: Sharpshinned Hawk (see more below).

Continue reading

Chimpanzees Use Spears to Hunt Bush Babies

Savanna Chimpanzees, Pan troglodytes verus, Hunt with Tools by Jill D. Pruetz and Paco Bertolani

Although tool use is known to occur in species ranging from naked mole rats to owls, chimpanzees are the most accomplished tool users. The modification and use of tools during hunting, however, is still considered to be a uniquely human trait among primates. Here, we report the first account of habitual tool use during vertebrate hunting by nonhumans. At the Fongoli site in Senegal, we observed ten different chimpanzees use tools to hunt prosimian prey in 22 bouts. This includes immature chimpanzees and females, members of age-sex classes not normally characterized by extensive hunting behavior. Chimpanzees made 26 different tools, and we were able to recover and analyze 12 of these.

Tool construction entailed up to five steps, including trimming the tool tip to a point. Tools were used in the manner of a spear, rather than a probe or rousing tool. This new information on chimpanzee tool use has important implications for the evolution of tool use and construction for hunting in the earliest hominids, especially given our observations that females and immature chimpanzees exhibited this behavior more frequently than adult males.

The full paper, from 2007, was available as a pdf when I visited (I don’t really trust these publishers and what articles by professors they will block access to later when they don’t clearly say it is open access – in fact the journal broke the link on the post I made about this in 2007 now that I checked – sigh).

The full paper isn’t filled with overly complex scientific jargon (as scientific papers can be). In that sense it is an easy read; it is a bit graphic for those that are squeamish.

Dr. Jill Pruetz maintains an interesting blog the Chimpanzees she studies: Fongoli Savanna Chimpanzee Project

Related: Chimps Used Stones as HammersOrangutan Attempts to Hunt Fish with SpearBird Using Bread as Bait to Catch FishCrows can Perform as Well as 7 to 10-year-olds on cause-and-effect Water Displacement Tasks

Virgin Births in the Animal Kingdom

Spectacular and Real Virgin Births

Scientists are discovering that virgin births occur in many different species; amphibians, reptiles, cartilaginous and bony fish and birds and it happens for reasons we don’t quite understand.

Initially, a virgin birth, also known as parthenogenesis, was thought to be triggered by extreme situations; it was only documented among captive animals, for example, perhaps by the stress, or isolation. A way to continue the bloodline when all other options had gone, when there was no other choice.

Not necessarily. It now appears that some virgin females produce offspring even in the presence of males.

Another interesting area of research for scientists. The value of sex to aid a species’ success is well understood. The value of being able to produce offspring when no males are around seems obvious also. But how this all works is quite interesting and again shows how much we have to learn.

Related: Fungus-gardening Ant Species Has Given Up Sex Completely (2010)Some Female Sharks Can Reproduce All by Themselves (2007)Amazon Molly Fish are All Female (2008)Bdelloid Rotifers Abandoned Sex 100 Million Years Ago (2007)

Deinocheirus is a Totally Bizarre Dinosaur

A very strange dinosaur has been uncovered, studied and explained by scientists. The dinosaur is from Mongolia about 70 million years ago.

“Deinocheirus is a totally bizarre dinosaur,” explains Phil Currie, professor and Canada Research Chair in Dinosaur Paleobiology at the University of Alberta. At 11 meters long and with an estimated weight of 6.4 tons, Deinocheirus was a behemoth to be sure—but hardly the giant tyrannosaur its massive arms may have suggested. Rather, the apparently disproportionately large forearms were more likely used for digging and gathering plants in freshwater habitats, or for fishing. Among its other unusual attributes are tall dorsal spines, truncated hoof-like claws on the feet to prevent sinking into muddy ground, and bulky hind legs that indicate it was a slow mover.

“Although the arms have been known since 1965 and have always aroused speculation because of their enormous size and sharp, recurving claws, we were completely unprepared for how strange this dinosaur looks,” says Currie. “It almost appears to be a chimera, with its ornithomimid-like arms, its tyrannosaurid-like legs, its Spinosaurus-like vertebral spines, its sauropod-like hips, and its hadrosaur-like duckbill and foot-hooves.”

Currie notes that Deinocheirus is a descendant of ostrich-like dinosaurs that were only slightly larger than humans, so its evolution into a giant, multi-tonne creature is almost certainly responsible for most of its unusual characteristics. “Its great size probably gave it some protection from the tyrannosaurid Tarbosaurus, which appears to have been relatively common in that part of Mongolia some 70 million years ago,” says Currie. To feed its great bulk, Deinocheirus was apparently an omnivore that ingested both plants and fish, as evident from fish remains found in its stomach contents.

“The study of this specimen has shown that even in dinosaurs like Deinocheirus, an animal that has been known for almost half a century, we can still learn surprising things about their anatomy,” says Currie. “Furthermore, it underlines the fact that even today, dinosaurs are still relatively poorly known. The fact that Deinocheirus is from the Nemegt Formation of Mongolia, one of the richest and most diverse dinosaur faunas known, hints that there are probably thousands of dinosaurs that we still do not know about from the majority of dinosaur localities in the world.”

Including poached dinosaur bones (stealing bones has long been a problem to the advancement of science) with the existing bones available to scientists allowed the new understanding of this amazing dinosaur. The now near-complete Deinocheirus specimen has been returned to its home for further study in the Mongolia Centre for Paleontology.

Full press release

Related: Ancient Whale Uncovered in Egyptian DesertNigersaurus, the Mesozoic CowDinosaur Remains Found with Intact Skin and TissueLobopodians from China (“the walking cactus” – an animal)Korea-Mongolia International Dinosaur Project

Nutrition and Digestion in Horses

Unlike cattle which have several stomachs (and there own interesting digestion system), horses have only one stomach. Like cattle their natural diet is grass. With feed provided by people, horses can run into issues they don’t experience from their natural diet. Fresh grass is fibrous and slows down digestion. If feed is used the feeding should be spread out several times during the day, due to the horses digestive system.

image of the digestive system of a horse

image via eXtention. The next 4 paragraphs are slightly edited quotes from the link.

The small intestine is the main site of digestion and absorption of protein, energy, vitamins and minerals.

The cecum is located after the small intestine of a horse and it functions much like the rumen of a cow (as a fermentative vat housing microbes which aid digestion). These microbes break down nutrient sources that would otherwise be unavailable to the horse.

The cecum and colon house bacterial, protozoal and fungal populations which function in microbial digestion of feed material in the digestive tract. Many different products of microbial digestion are absorbed by the horse.

Among other benefits, incorporating long-stem forage into rations increases particle size of ingested matter, thus slowing rate of passage. It also increases dry matter intake, thus stimulating water intake.

Nutrients and Common Feed Sources for Horses from the extension service (USA land grant universities)

Carbohydrates provide the majority of a horse’s energy. Non-structural carbohydrates, such as starch and glucose from grains and gums and pectins from fiber, are readily utilized as energy sources for the horse. The enzyme amylase breaks down non-structural carbohydrates into glucose and simple sugars, which are absorbed in the small intestine.

Structural carbohydrates, such as cellulose and hemicellulose in plants, can only be broken down by bacterial enzymes in the cecum and colon. The microorganisms convert these carbohydrates to volatile fatty acids (acetate, propionate, butyrate), which can provide 30 to 70 percent of the horse’s energy requirement.

Fibrous feeds are a very important part of the horse’s diet. They provide nutrients for both the horse and microbes in the hindgut as well as stimulate muscle tone and activity of the gastrointestinal tract.

Mineral supplements are usually required in the horse’s diet. Macrominerals are added to a horse’s diet to balance the ration to meet mineral requirements.

Human raised horses usually have some grazing but get some or much of there food needs from feed. Those feeds often supplement normal food for wild horses with beets, apples, carrots and other sources. In addition the horse food supplements include minerals, fiber and even pre-biotics and pro-biotics (just like our processed food does).

As a general rule, horses need 1 to 2 quarts (2 to 4 liters per kilogram) of water per pound of dry matter consumed. Of course, other factors can increase the water need, such as exercise (since it results in water loss through sweating).

Related: Great Webcast Explaining the Digestive SystemsEnergy Efficiency of DigestionTracking the Ecosystem Within Us

USA Designates Large Areas of New Mexico and Arizona as Critical Habitat for Jaguars

The U.S. Fish and Wildlife Service has designated 764,200 acres of critical habitat for the jaguar (Panthera onca) under the Endangered Species Act (ESA). This habitat is found within Pima, Santa Cruz and Cochise counties in Arizona, and Hidalgo County in New Mexico.

The final rule reflects the following changes from the July 1, 2013, critical habit at proposal: exclusion of Tohono O’odham Nation lands (78,067 acres) as a result of the Tribe’s efforts working in partnership with the Service to conserve jaguar and other listed species’ habitat on the Nation’s sovereign land. Exemption of Fort Huachuca lands (15,867 acres) due to the conservation benefits to the jaguar provided in Fort Huachuca’s approved Integrated Natural Resource Management Plan.

The revised proposal was based on an updated habitat modeling report that more accurately reflected habitat essential to jaguars in northwestern Mexico and southwestern United States.

Mexico borderlands area is very different from habitat in Central and South America, where jaguars show a high affinity for lowland wet communities. Jaguars have been documented in arid areas of northwestern Mexico and southwestern United States, including thornscrub, desertscrub, lowland desert, mesquite grassland, Madrean oak woodland and pine oak woodland communities. Critical habitat in the United States contributes to the jaguar’s persistence and recovery across the species’ entire range by providing areas to support individuals that disperse into the United States from the nearest core population in Mexico.

Critical habitat is a term defined in the ESA and identifies geographic areas containing features essential to the conservation of a threatened or endangered species and that may require special management considerations or protection. The designation of critical habitat does not affect land ownership or establish a refuge, and has no impact on private landowners taking actions on their land that do not require federal funding or permits.

Related: Jaguars Back in the Southwest USA (2006 post)Big Cats in America (2004)Mountain Lions Returning to the Midwest USA for the First Time in a Century (2012)Backyard Wildlife: Mountain Lion

Continue reading

Why do Bats Transmit so Many Diseases like Ebola?

Bats are generally wonderful creatures and helpful to us. For example, they eat lots of insects that are annoying (like mosquitoes) and pollinate lots of plants. Of course, they also eat lots of good (for us humans) insects but the insects still seem to be able to fulfill their environmental niches so all is good.

And they are flying mammals which is, of course, cool.

But bats also transmit virus to us, which do us lots of damage. As the video explains as we have intruded into bat territory and chopped down their natural feeding spots we have come into contact with them more. And because bats evolved to be very resilient to virus and they live in large colonies (for easy transmission of the viruses to lots of bats) they can host viruses and survive long enough to infect lots of other bats, and to infect us if we meet them.

I actually didn’t know this (mentioned in the video): most viruses have a very difficult time surviving even with temperatures a bit above the normal human temperature (98 degrees Fahrenheit). Bats, while they fly, have internal temperatures that soar to 104 degrees (40 degrees centigrade) which kills off most viruses, but certain hardy viruses survive. This also explains why we run fevers when we are sick (which then can kill off viruses) – which I am sure I learned at some point but I forgot. But for the bat viruses that strategy doesn’t work.

Bats, of course, are not impervious to disease. In the USA a disease has killed more than 90 percent of the cave bats in Eastern states.

One of the causes of the current ebola outbreak is believed to be people eating bats in West Africa.

Related: Ebola Outbreak in Uganda (2007)A Breakthrough Cure for Ebola (2010)Swine Flu: a Quick Overview (2009)

Continue reading

Crows can Perform as Well as 7 to 10-year-olds on cause-and-effect Water Displacement Tasks

In Aesop’s fable about the crow and the pitcher, a thirsty bird happens upon a vessel of water, but when he tries to drink from it, he finds the water level out of his reach. Not strong enough to knock over the pitcher, the bird drops pebbles into it — one at a time — until the water level rises enough for him to drink his fill.

Highlighting the value of ingenuity, the fable demonstrates that cognitive ability can often be more effective than brute force. It also characterizes crows as pretty resourceful problem solvers. New research conducted by UC Santa Barbara’s Corina Logan, with her collaborators at the University of Auckland in New Zealand, proves the birds’ intellectual prowess may be more fact than fiction. Her findings, supported by the National Geographic Society/Waitt Grants Program, appear today in the scientific journal PLOS ONE: Modifications to the Aesop’s Fable Paradigm Change New Caledonian Crow Performances.

photo of Corina Logan

Researcher Corina Logan with a great-tailed grackle and a night heron at the Santa Barbara Zoo. The zoo is one of the sites where Logan is gathering data to compare and contrast the cognitive abilities of grackles and New Caledonian crows.
Photo Credit: Sonia Fernandez

Logan is lead author of the paper, which examines causal cognition using a water displacement paradigm. “We showed that crows can discriminate between different volumes of water and that they can pass a modified test that so far only 7- to 10-year-old children have been able to complete successfully. We provide the strongest evidence so far that the birds attend to cause-and-effect relationships by choosing options that displace more water.”

Logan, a junior research fellow at UCSB’s SAGE Center for the Study of the Mind, worked with New Caledonian crows in a set of small aviaries in New Caledonia run by the University of Auckland. “We caught the crows in the wild and brought them into the aviaries, where they habituated in about five days,” she said. Keeping families together, they housed the birds in separate areas of the aviaries for three to five months before releasing them back to the wild.

Continue reading

  • Recent Comments:

    • Douglas Sciortino: I’m still skeptical. Sure they got the board to float, but what happens when you...
    • ahmedmanoo: It’s really a wonderful picture
    • Nasiru Dauran: It was very unfortunate for missing such a great hero. I haven reading some of his...
    • Matt: I’m impressed with these innovative inventions. Glad that we still have young scientists that...
    • Burhan Nova: Wow wow wow! Fantastic idea man !
    • Stella: Very interesting. Imagine a “available tonight” in hidden ink. edit: didn’t...
    • Tanzila: It’s very essential post for us. we learn more about source of Independent Postdoctoral...
    • Ahmed: Oh i did not know that
  • Recent Trackbacks:

  • Links