Avery writes:


I enjoyed your episode discussing CWD, and as a wildlife biologist I thought I could answer a few of the questions you had on wildlife and hunting. Although I am professionally focused on small game, I do hunt the big cervids, and assist with CWD monitoring efforts. 

Emerging Disease or Emerging Awareness: It is both. The disease is definitely spreading and becoming more prevalent. It has not just spread gradually through wild populations, but its distribution was greatly expanded by the captive cervid industry you discussed. Unfortunately they are high density operations (at least relatively) with increased rates of disease transmission, and then animals get  put on trucks and quickly move long distances.  They should have fences to keep the captive animals separate from wildlife, but they are anything but biosecure. Spread in wild populations may be accelerated by feeding operations designed to keep heards alive through hard winters, but also to keep animals out of town and out of livestock feeding areas. As awareness has increased so has testing. It seems that when adequate samples are collected, it is not unusual to get positive results.

All the cervid farms where CWD has been found are not depopulated, although many are.

The USGS has a map of areas where CWD has been found, and also showing cervid farms with disease. If you look at western Wyoming there is a lack of farms, but there are a lot of state run feeding operations for elk.

Gut Piles: In the northeast most hunting is on small acre private ground where people usually are close to home, or somewhere to hang a deer, so there may be more people bringing an un-dressed deer home. However in western hunting, I would say 95% or more of people will gut a big game animal where it is killed. Both to allow the animal to cool quicker, which preserves the quality of meat, and to lighten the animal if it is to be dragged to a road. Much of the time we are packing out quarters, and definitely do not pack out the GI tract, but some may pack the heart and liver.

Gut piles are also notably a major source of lead toxicity in California condors and other scavenging birds.

Urban Deer – Why are they not culled or hunted to low levels: Basically, because we can’t. In western states deer will often move into urban areas during the winter months to find accessible food and to escape hunting pressure (both human and non-human predators). These deer are often part of desired populations, and hunting in urban areas is hazadors (not to mention illegal). We do have limited cull programs and trapping programs, however they are expensive and hard to scale beyond small problem areas. In eastern states there often is simply not enough hunting pressure despite very liberal permit numbers.

Mixing Game Meat With Domestic Meat: Burger and sausage is generally at a 10:1 or less ratio if using pork belly or bacon.

Do trains hit deer? They sure do. We occasionally have a train bowling pin down a herd standing on the tracks. A few years ago we found a radio collar that was very smashed due to the elk it was attached to getting hit by a train.

Thanks for the great podcast! It has been hugely informative and helpful.


Wildlife Biologist for the Utah Division of Wildlife Resources

P.S. mid 40’s F, blue skies, with no precip today.

Jeff writes:

Happy whatever day it is that you’re reading this!

Regarding #878: There was a point in the discussion that Dickson mentioned that it has been estimated that the carrying capacity of the earth is 12 billion. I have to say that we are already far past the carrying capacity at almost 8 billion as shown by the decline in wildlife populations globally that has been going on for decades:






These declines are more severe than those seen in the fossil record prior to previous extinction events and so signal that we are heading for an imminent extinction event if we do not reduce the human load by developing policies that a) get people to stop having babies to drive our population to well below two billion ASAP and (b) replace our extractive economy with a sustainable one that protects wildlife and its habitat and ends the animal-based meat industry.

To see just how out of balance the current situation is consider that human biomass is estimated at 0.06 Gtons Carbon (GtC) (see https://www.pnas.org/doi/10.1073/pnas.1711842115) while that of all wild mammals is estimated at 0.007 GtC. We’re almost 10X their biomass. Now add that of our livestock, estimated at 0.1 GtC and you see that we are 22.8X the biomass. 

Also, while a bit simplistic, consider that 5% of the earth’s population, the US, uses about 25% of the earth’s production, which means that for all people to live at our standard of living, which they do, the earth would need to increase its production by 5, which is impossible.

Nothing we do is sustainable, which is the high level consequence of our abject brutality that we bring upon those we don’t value except as a means to satisfy our desires. Meat is not necessary to sustain human life or health, which can be sustained by a plant based diet, and as we do not need meat there is no valid reason to brutalize nonhuman animals to merely satisfy our desires. Nonhuman animals have the same claim to rights that we do because we consider ourselves moral. It is that simple.

Sincerely, Jeff

Ingrid writes:

Dear TWiV team,

Thanks for another great epitope!

Re ‘noticing’ a prion disease emerging in people from an animal source, and then ‘working backwards’ from that point, the way we do with viral outbreaks – this is potentially a much worse problem with prion diseases, because the main known such disease (Variant Creutzfeldt-Jakob disease or vCJD, aka “mad cow disease” in people) has a ten-year and possibly longer incubation period, and is 100% fatal. There is even some concern in the UK that there might still be another wave of victims (who have not yet exhibited any symptoms) from their original spillover event, since some small minority of their population seems to show some of those prions in blood samples.

If U.S. deer populations are currently experiencing a suspicious new spike in prion disease, which might conceivably be a new type that could infect humans, saying “Oh, but no people have come down with it” is meaningless. Worst case scenario, if it is possible for people to contract it by eating these deer, the disease might not be noticed for another ten years or more, by which time a lot of hunters and their families could be infected. Even if deer hunting got banned at that point, people could keep coming down with symptoms and dying for yet another ten more years.

So it makes sense to me that there is a high motivation to try to suss out how dangerous this spike in deer might be, even if no ideal experiments can be done. Obviously you can’t experiment on people. And while injecting lab animals’ brains directly with the prions might not be an ideal scientific experiment, on the other hand, infecting via the normal route by feeding prion-tainted food would likely require a many-year-long incubation period before getting any results, so a better experiment design but not very practical in the short term. If several non-ideal experiments even hint at potential danger, I think it might be enough to lead to some regulatory change in deer hunting, or at least widespread warnings being issued, even if those experiments don’t definitively prove that the disease can be transmitted to people.

Thanks again for all the TWi’s!


Timothy writes:

Re “Gut piles”, 

It is standard practice in Texas to “gut” the deer after a kill and clean/quarter the deer carcass, first step is taking the guts in a bucket and throwing it out for the coyotes to eat. I’m not sure what Amy is discussing when weighing the deer. Never done in my life and never seen it. So this is what that research paper is mentioning.

Neva writes:

Hello TWIV Gurus,

Your podcasts have been helping to keep me sane and provide me with wonderful reliable information -also they kept getting better and better. 

I have happily infected many people with TWIV. I’m tickled to report that my high school granddaughter who has developed a love of biology is now infected. Achievement unlocked!

Possible article pick. This seems to be a good general overview of the state of EBV research and initiatives. Since I have a nephew devastatingly afflicted with MS I have been following this closely.

Can we vaccinate against Epstein-Barr, the virus you didn’t know you had?


Another pick might amuse you is from Paul M Sutter who has a podcast and YouTube channel, Ask a Spaceman, discussing physics and cosmology. Some time ago he posted himself reading one of his physics papers. With very humorous self-depreciating style, he suggests it as a sleep aid!

My very best regards to the whole lovely TWIV universe.

Neva from Buda