Friday, 31 May 2013

why is inbreeding so bad?

one more thing—going back to poni's presentation on cheetahs, i was wondering exactly why inbreeding is so bad for them (and for organisms in general). i know that it results in increased homozygosity of many alleles in the offspring organisms, but i wasn't sure exactly why that was such a bad thing. of course if a family carries a masked recessive gene that causes a disorder, inbreeding would increase the chances of its expression, but i'm wondering if there are other ways inbreeding compromises organism fitness.

upon further research, it looks like all of the problems associated with inbreeding are basically just iterations of that same concept. deleterious recessive alleles carried by a family can come together homozygously in offspring, leading mostly to a characteristic pool of less critical problems and less commonly to catastrophic phenotypes. the most common effects of inbreeding include reduced fertility, facial asymmetry, increased infant mortality, stunting and immune system compromise, while more serious genetic disorders crop up depending on the family. these effects serve to cull the population of inbred organisms—lower fertility and poorer physical condition make it difficult for inbred animals to survive until reproductive maturity, let alone to actually reproduce.

the concept applies at the population level as well. the term "inbreeding depression" is given to the phenomenon of reduced population fitness due to genetic similarity as a result of inbreeding. reduced immune system function and increased likelihood of particular susceptibility to a certain disease or disorder can render inbred populations less likely to survive and proliferate. if one virus or disease is particularly deadly to an individual, inbreeding makes it more likely that that same virus will have similar effects on the rest of the population. cheetahs provide a sad example of this—a 1990 study on one cheetah population recorded a 90% prevalence of feline infection peritonitis and a 60% mortality rate.

surprisingly, some species are not subject to inbreeding depression. generally, these species emerged in very small but viable populations and have been inbred since their origin. as a result, deleterious alleles are eliminated from the population extremely early on, and further inbreeding presents little risk of depressing population fitness by exposing harmful alleles.

more info here:


how do shepherd dogs know how to herd?

hi y'all,

i really liked the anatolian shepherds we met at cheetah outreach—i still don't understand how an animal that big and capable of doing so much damage can be so sweet and friendly! i was curious about how shepherd dogs learn their herding behavior and didn't manage to ask any of the staff, so i thought i'd look it up and share with you guys.

from what i found, it looks like herding is an innate, instinctual behavior in dogs, but it shows up in varying degrees depending on the breed. most dogs won't just start herding animals when they see them, and require a little training before the behavior will fully develop. even shepherd-breed dogs won't necessarily herd on their own and require a little prompting. the behavior can be pretty hilarious once the dogs figure it out though—shepherd dogs especially will try to guide or keep together groups of people, toddlers, other pets, the mailman, etc.

i was also wondering how that instinct to herd got there in the first place, so i looked into that as well.
apparently, herding is a hunting behavior that has been modified over time through selective breeding by humans. dogs use different methods of herding—"heelers" nip at the heels of their flock in order to get the animals to move, while "headers" stare down animals directly in front of them and get them to change direction and "living fence" strategists simply block the flock from moving in a certain direction by being in the way. some breeds can act both as heelers and headers, with the dogs at the back of the flock heeling and the ones at the front heading. many dogs also will bark in order to get their flock moving. pretty amazing what selective breeding can do—hard to imagine training a huge anatolian shepherd to guide rather than devour a flock of sheep!

information from here:


Monday, 27 May 2013

The Language of Love

Alec recently posted a blog post that put mosquitoes in a pretty negative light. However, while working on my latest presentation on mating systems of sexual animals, I came a cross a really interesting article about mosquitoes and mating that showed their more...romantic side.

In a study conducted in 2009, two Cornell scientists discovered the love song of the Aedes aegypti, the species of mosquitoes that transmits viruses that cause yellow fever and dengue fever. These scientists found that when mating, male and female mosquitoes will adjust the whine, or frequency, of their wings until it converges to a harmonic of the fundamental frequencies of each mosquitoes' whine. Wait, what does that even mean?

"A harmonic of a wave is a component frequency of the signal that is an integer multiple of the fundamental frequency, i.e. if the fundamental frequency is f, the harmonics have frequencies 2f, 3f, 4f, . . . etc." A female's fundamental frequency is usually at 400Hz, while a male's is at about 600Hz. When mating, male and female mosquitoes will raise their whines to about 1200 hertz. Talk about meeting each other halfway!

It is so interesting learning such quirky tidbits about some of the vilest and most hated creatures in our ecosystem. It makes one really appreciate those little critters.

Watch the video here: Mosquitoes Mating


Sunday, 26 May 2013

Sharks, orcas, and serotonin highs

To follow up on my Great White Shark presentation last week, I pose the question: if a great white and an orca were to face off, who would win?

Turns out this actually happened! In 1997, a bunch of whale watchers in a boat off the coast of the Farallon Islands (about 30 miles from San Francisco) witnessed an orca attacking a great white shark. Most of the action occurred underwater, but scientists have pieced together the most likely sequence of events.

First, the orca deliberately changed its path to reach the shark and rammed into it at full speed. The shark, which had not been aware of any danger, was stunned and confused. Taking advantage of its confusion, the orca grasped the shark on the back of the head and turned it upside-down. The shark panicked and its brain released a flood of serotonin, a neurotransmitter, that put the shark into a trance-like state. The orca proceeded to feast on the shark's nutritious and delicious liver.

So next time you bump into a great white trying to eat you, all you have to do is flip it over! Easy, right?


Saturday, 25 May 2013

Elephants Walks: Too Dangerous for Tourists?

Hi all!

In light of my recent elephant walk on the Garden Route tour, I wanted to do a bit more research about African elephant handling. Colleen, our tour guide had to change our elephant walk plans at the last second because the reserve that we were going to visit had an accident the previous week. She said that the elephants killed a couple of the trainers one morning, and therefore the park was closed.

I wanted to find a news article to confirm or deny this story, but I could not find a current one online. I did stumble upon this article about an elephant handler who was trampled to death in Johannesburg last month. Reading this article definitely made me think twice about the domestication of these massive creatures! The accident consisted of the handler falling off the back of an elephant, but there was "no maliciousness of any sort displayed by the elephants."

There have also been quite a few elephants overturning cars in the reserve, but the authorities stated that the tourists did not take proper precautions. In the most recent case, the tourists turned off the car when the elephant began charging... the owner of the reserve thought that they should've just driven away.


Friday, 24 May 2013

cheetah housepets

poking through the news this morning and came across this story:
a couple who adopted two cheetah cubs AND ARE LETTING THEM PLAY WITH THEIR INFANT CHILDREN. i kind of couldn't believe it when i read it, and the hilarious comments at the bottom of the article are of the same mind—how could sane parents expose their kids to that sort of danger?

i was curious if stuff like this had been successfully accomplished before, so i looked into cheetah-human bonding a little more. information from the cheetah outreach website calls cheetahs poor pets due to unpredictable behavior, but apparently lots of wealthy people in africa and the middle east ignore this and try to keep them as pets anyway. cubs are more docile and harmless, but as they mature they become more spontaneously aggressive and dangerous.

from the animal's standpoint too, captivity is harmful—while cheetahs are endangered and some owners claim they're helping the species survive, domesticity disallows many naturally occurring behaviors and can cause health problems. owners often have no idea how to properly care for the animals, and act on superstitious beliefs that feeding them canned cat food, milk or cheese will keep them calm and unaggressive. this diet can lead to bone deformities, blindness, deficiencies and other issues in the cats. finally, when the animals become too large, expensive or inconvenient to handle, they're released back into the wild, where they're now unfamiliar with how to survive, or simply left outside in cages to die.

clearly, many of these problems stem from awful, uneducated owners, but it's also evident that cheetahs are intrinsically wild animals unsuited for captivity as pets. tons more info here:

but maaaaan do i wish i could have a cheetah pet...


Tuesday, 21 May 2013

mosquitoes love me

our room gets stuffy so aditya and i open the window to let some fresh air in every day, and inevitably, mosquitoes wander in too. they've been eating me alive this quarter, which i'm kind of resigned to at this point, but to add insult to injury i don't think aditya's gotten a single bite yet.

aditya's all suave about it—he says stuff like "awww don't worry, it's just because you're so sweet"—ha. it made me start wondering what the actual reason for mosquitoes picking one person over another is though, so i looked into it a little.

turns out our skin gives off odorants that are metabolites of natural biological processes, and mosquito antennae bind them and sense our presence that way. which metabolites we generate and how many mosquitoes we attract are most strongly influenced by the amount of carbon dioxide in our breath, pregnancy, alcohol consumption and blood type.

so far as i know, neither aditya nor i are pregnant. i'll have to check with him to make sure but i'm pretty certain that one's not a factor here. type O blood is the most attractive to mosquitoes, but i'm not type O and i'm not sure what aditya is. however, different genotype lead to different levels of blood metabolite secretion, so i might just be putting off more of a signal than him. increased carbon dioxide emission in breath and increased body temperature (both on its own and as a result of alcohol consumption) also attract mozzies—not sure who's breathing out more CO2 between the 2 of us, but aditya doesn't drink and i'll have a beer or glass of wine after dinner every now and then, so that may be a deciding factor. mosquito bites or giving up beer? why does the universe give me these terrible choices?


read more here:

Friday, 17 May 2013

South Africa's Grasslands are in Danger

South Africa's Grasslands are in danger! I came across this article that discusses the Grey Crowned Crane, one of South Africa's most beautiful and majestic birds. This crane is losing its habitat, and is currently critically endangered in South Africa. There are less than 260 birds remaining in the wild, and habitat destruction is a major issue!

The biggest threat is mining t this time. Apparently open-cast coal mining destroys large areas. Crop agriculture is also a major issue, because the diversity of the land is reduced greatly when large plots of land are used for farming. Saving the landscape of South Africa is not necessarily the focus of many conservation corporations, which usually focus on the more majestic safari animals.

Grasslands are 80 percent herbaceous plants and forbs, and only 20 percent grasses. The forb is critical to the ecosystem, and it is typically the first to be destroyed. There are thousands of plant species that thrive in grasslands, and much of the ecosystem is dependent on the health of these habitats.

Here is the article if you'd like to check it out:

-Brittany Bankston

Monday, 13 May 2013

Another possible solution for the rhino

Continuing on the rhino poaching topic, with the Black Rhino, Northern White Rhino, and Javan Rhino nearing extinction in the wild,  it is high time for conservationists to enact programs to save these species. Historically, species like the Southern White Rhino, Przewalski's Horse, and bison have returned from the brink of extinction due to successful captive breeding programs in which species are bred in zoos and nature preserves, then reintroduced to their original habitats. If poaching cannot be shut down and habitats protected effectively over the next couple years, the same approach may be necessary to keep the critically endangered species of rhinoceros alive.

Captive breeding and reintroduction programs are criticized because they do not prioritize the need to restore habitat, and they are costly and sometimes fail. Most of all, people argue that we should rescue species before they reach the brink of extinction. But when the strongest efforts to save the rhino have not been able to keep their numbers from declining, there may be no choice but to work with the captive rhinos we have left. The IUCN Species Survival Commission chair Simon Stuart said, "Human beings are stewards of the Earth and we are responsible for protecting the species that share our environment." In response, I would argue that we are responsible for protecting not all species, but the species that we have directly or indirectly caused to decline. If the last straw for protection means captive breeding, then we have no choice but to try it!


Meerkat Manor: Mobs at War

Check out this awesome video depicting two meerkat mobs at war in the wild!

This show is awesome, there are lots of really interesting episodes, and it is almost as addicting as any reality show on MTV. The Whiskers mob is full of different personalities and dramatic interactions. Each meerkat has their own name, and the communities display quite a few human qualities in the wild! There are irresponsible teens, loyal friends and families, and rival mobs. Check it out if you have some free time!

The show has fantastic ratings, and has done really well in the documentary community. It has won countless awards, and more importantly, it has won over the hearts of America. This particular video shows some intense never before seen footage of Meerkats, and presents them in a way that is breaking ground in the documentary community.
Happy Weekend,


Sunday, 12 May 2013

don't feed the birds!

hannah rusk and i went down to the waterfront this weekend and had a fun time hanging out near the docks with the seagulls. the birds were so bold, they come right up to you and stare you down until you give them food, and if you don't after a few minutes they give these hilariously annoyed squawks and stalk away toward other people!

i thought it was an interesting situation—seagulls eat a huge range of foods in the absence of humans, but these birds were clearly surviving mostly on scraps tossed to them by tourists. i thought it just couldn't possibly be a healthy situation for the birds so i looked into it a little, and humans tossing food is a way bigger problem than i thought.

bread (the most common food we saw tourists offering) is a pretty nutritionally poor food, and when tourists provide enough of it that it becomes seagulls' primary food source, the birds can become malnourished. ducklings learn to rely upon human handouts and fail to learn to forage for themselves properly. the yeast in bread can cause a condition called sour crop, which is a fungal infection that can lead to putrifaction of food within the birds' digestive tract and severe illness. eating moldy bread can cause aspergillosis, a fatal lung infection. tossing bread also attracts pests like rats and insects, which nobody wants to have around. finally, rotting bread in smaller bodies of water (this happens more often in ponds with ducks) can alter oxygen levels and lead to algae blooms that can harm the birds. for a complete list of detrimental effects, look here:

so do the birds a favor the next time you have food with you—don't give them any!


Monday, 6 May 2013

What happens when 15000 Crocodiles escape from captivity?

  Back in January 2013, a South African reptile farm located along the border of Botswana released 15000--repeat: fifteen thousand--crocodiles into the Limpopo River. After torrential rains caused the Limpopo River to flood, the farm owners decided to open their gates so as to avoid destruction of the walls of their home. Consequently, 15000 crocodiles were let loose into the Limpopo River. Most of the crocodiles were discovered in the brush and water of the surrounding area, while some were found in very unusual places such as a school's rugby field. The son-in-law of the farm owner was reported to have saying, "There used to be only a few crocodiles in the Limpopo River. Now there are a lot." Oh.

Read more about the escape:

Map of South Africa and Botswana:


Sunday, 5 May 2013

News Article: Swallowed by a Hippo

Yesterday, May 4th, 2013, a news article was written about a hippo attack survivor. An alarming story of a 27 year old man who had a business taking clients down to the Zambezi river. He describes his attack being very sudden, where he found himself noticing half of his body had been engulfed in something very slimy, a hippo's mouth!

The man was able to wriggle around and escape, but the hippo attacked again! He was thrown around and badly wounded. He had been told he would have lost both arms and a leg, but fortunately they were able to save 2 out of 3 of his mangled limbs. This man was lucky, but his friend Evans was killed. What an experience! Reading this article made me really think about the place of humans in a wild environment. Are we really welcome into the homes of these wild animals, and should we continue to enter into their territory? This man was able to leave with his life, but many humans each year are not so lucky.

Here is the article I found about this man's remarkable story!

I also decided to do some follow up research about human deaths by hippo attacks. I stumbled upon a website that counted hippo deaths at a whopping 2,900 people per year in Africa! WOW!

Happy Sunday,

a rat asleep in the street

hi guys—

we were walking back from salt river this last week and came across a rat asleep right out in the open on the sidewalk. i thought it was a pretty strange sight, mainly because most of the rats i've seen living in cities are incredibly skittish and avoid confrontation at pretty much all cost.

i was wondering if there might be something wrong with the rat and decided to look into it a little—turns out there are a variety of parasites that rats can get that actually modify their behavior to optimize conditions for the survival of the parasite. one parasite in particular, toxoplasma gondii, prefers to live in cats, and so will form cysts in the rat's brain causing loss of inhibition and increased exploration of novel stimuli, resulting in higher chances of being eaten by a cat and passing the parasite on. more here:

not sure if that was what was happening to the little guy we saw on the street, but the whole parasite thing is fascinating—unbelievable how some organisms adapt to survive!