It seems like being bipedal creates vulnerability to predation. What has survived tends to be fast or flies.

Kuru is absolutely caused by cannibalism. It started off because sporadic CJD happens in about 1/1m people and because of ritualistic eating of the brain and spinal cord it became transmissible variant CJD.

About 90% of CJD is sporadic.

[removed]

How Fast Can a Kangaroo Run?

In terms of covering ground kangaroos have some impressive statistics. Interestingly kangaroos don't run, they jump. Kangaroos are recognized in the jumping category as the best jumpers in the world. They can spend more than 30 minutes jumping as they have excellent resistance and know how to manage their energy well.

Cannibalism is just a form of transmission, prions self propagate by causing misfolding of healthy PrPs which accumulate into amyloids and cause disease.

Yes but only a few which are primarily land based, and capable of covering ground as well as a kangaroo or human. Emus, ostriches, and a few others.

Small electric aircraft already exist. Given the interest in electric aviation by many big name companies including Tesla, the constantly improving battery tech, and the way the companies talking about alt fuels are either still in development or actively dragging their feet in hope that people give up and let them keep making gas cars, we may well end up going all electric before alternate aviation fuels are available...

That's also the way my anesthesiologist explained it to me for an arm surgery. They used a nerve block to make my arm go numb.

We generally don't use capacitors to power devices because it discharges most of it's energy at the quickly unlike a battery which as a slower mostly constant output. It's useful if you want to dump a lot of energy at once like a camera flash or defibrillator, not so much when you want to power a motor.

Are prions completely absent in healthy individuals? If they're present at low levels, then cannibalism would allow bioaccumulation of them.

Agreed. Jet A1 is just clear Kerosene. Avgas has lead but is rarely used and not in commercial flights because it’s so expensive.

[removed]

Could also argue kangaroos are tripedal, as their massive tail is often used to support their weight.

[removed]

It is both regulation (anything aviation takes ages to get certified - both fuel and engines using it must be certified to be legal to use) and also the old engines which simply can't run on unleaded gas.

It is not a question of octane number so much but engine lubrication, fouling and knocking. Older planes with engines not designed for unleaded gas would require additives for this reason - the same as old cars do when fueled with unleaded gas.

Aviation is a slow moving field - not many people still drive cars made in the 60-70s but there are many many planes that are even older than that still in service (esp. with private owners, flight schools, etc.) - and none of them can handle unleaded fuel without additional steps. Either using fuel premixed with an additive (the most common solution) or an expensive engine modification which may not even be available for the old engine types still in use.

Oh and the unleaded avgas is more expensive than regular one too. Given that the price of fuel is one of the largest costs when flying, it is likely not going to help its popularity either.

There is also a promising push within the industry that new build aircraft are fitted with engines that run on alternative fuels. Rotax engines that run on MOGAS (or standard car-grade gasoline/petrol) are becoming more popular. Diamond Aircraft from Austria fit the majority of their aircraft with a modified Mercedes Benz Diesel engine, which has its own issues, but removes the Lead content.

The issue in General Aviation is that these piston aircraft, with the right levels of maintenance, can run for decades, the majority of aircraft that students train in these days are 40-60 years old, still completely safe, and still completely legal, but running on technology that would otherwise be completely obsolete. However these engines keep going because they have the safety record to back them up, and rule number 1 of flying is to reduce risk and maximise safety at every opportunity.

>So if you're ever in hand-to-hand combat with a vicious alien xenomorph queen, about to be ripped to shreds, and your last hope is to release the air lock... then it was nice knowing you.

Damn

If blowing the airlock isn't going to work, how do you actually deal with this scenario?

There's an unleaded avgas available that got FAA approval last year. With how slowly aviation moves it may take another 10 years before lead gas gets replaced completely.

[removed]

I think the question is based on a misapprehension. Kuru and Mad Cow Disease are not caused by cannibalism. This seems to be quite a common belief and is a misunderstanding. The cannibalised individual has to be infected in the first place. Which is relatively rare. What can be said, perhaps, is that cannibalism is possibly the only way the infection can be transmitted from individual to individual as consumption of infected tissues is pretty much the only way it can pass from person to person. However, kuru is not a fundamental risk of cannibalism in and of itself. If there isn't kuru in the population already, cannibalism itself isn't going to cause it to emerge.

I think the myth came from a group of people who engaged in ritualistic cannibalism of their dead. They had kuru in the population already from eating infected ungulates and people were dying of kuru and then being eaten due to the traditional practices, which just passed the problem on. But the cannibalism wasn't the source of the condition, just the means of transfer.

I forgot about the quokkas. Quokkas can stand erect.

Why do we even use avgas with aviation piston engines being what they are today i.e. not particularly advanced? Is it regulations, so engine certified for 100LL couldn't be easily switched to a fuel with less octane number?

But with avgas being just 0.14% of all fuel consumption in US I guess it's not a national issue though people living near small airports could be concerned.

[removed]

Not really an answer to your question, but a fun fact. In order to stand upright, human legs have to connect directly downward from the pelvis. This means the opening which baby’s pass through during childbirth is smaller than in 4-legged animals where the legs connect at an angle to the pelvis. In order to fit the baby through the narrower passage, we evolved to give birth earlier when the baby is smaller. See, most mammals have a similar gestation period relevant to their life span. The human gestation period should be around 14 months. So that’s why newborn babies are such helpless potatoes when they’re born at 9 months.

Edit: I kept saying tailbone when I meant pelvis.

[removed]