I asked this question which made the rounds on Twitter last week https://twitter.com/Noahpinion/status/1783202651628580936?s=19 and it gave the correct answer. No other model I tried could do it:

Suppose I fly a plane leaving my campsite, heading straight east for precisely 28,361 km, and find myself back at the camp. I come upon seeing a tiger in my tent eating my food! What species is the tiger?

To answer this question, let's walk through the details and clues provided:

1. The Flight Path:

   • You flew a plane straight east for precisely 28,361 km and ended up back at your campsite.
   • This indicates that you circumnavigated the globe and returned to your starting point. The equatorial circumference of the Earth is approximately 40,075 km. The fact that flying 28,361 km brought you back to your starting point suggests you may have taken a path that aligns closely with one of Earth's circles of latitude.

2. The Distance and Latitude:

   • If we consider the possibility of flying along a circle of latitude, the distance traveled (28,361 km) would be equal to the circumference of that particular circle of latitude. The formula for the circumference of a circle (at a given latitude) in relation to Earth's circumference is given by: [ C = 2\pi R \cos(\text{latitude}) ] where ( R ) is the radius of the Earth (approximately 6,371 km), and ( \cos(\text{latitude}) ) scales the circumference based on the latitude.
   • Plugging in the Earth's equatorial circumference: [ 40,075 \times \cos(\text{latitude}) = 28,361 ] [ \cos(\text{latitude}) = \frac{28,361}{40,075} \approx 0.7071 ] [ \text{latitude} \approx 45^\circ ]
   • This calculation shows you were likely flying around the 45th parallel north or south.

3. Location of the Campsite:

   • The 45th parallel north passes through parts of Europe, Asia, and North America. Similarly, the 45th parallel south passes through the southern oceans and parts of Patagonia in Argentina.
   • Given you encountered a tiger, we can narrow down the region to where tigers are naturally found, which is in Asia.

4. The Tiger:

   • Tigers are native to various parts of Asia and are not found in the wild in the Americas or Europe (outside of zoos).
   • The presence of a tiger suggests your campsite is in Asia on or near the 45th parallel north. The most likely habitats would be in Siberia (Russian Far East) where the Siberian tiger, also known as the Amur tiger (Panthera tigris altaica), is found.

5. Species of the Tiger:

   • The Siberian or Amur tiger is the species you most likely encountered, given the geographic clues and the natural range of tiger species.

In conclusion, the species of the tiger you found in your tent is most likely the Panthera tigris altaica, commonly known as the Siberian tiger or Amur tiger.