When US national parks closed in 2020, scientists tracked 229 mammals in 14 parks; animals near developed areas began using those spaces differently from before

We can all remember Spring 2020. Banana bread, Zoom happy hours and staring at walls. However, places such as Yellowstone and Zion saw a huge change in activity at their trailheads, with no people in the car parks or visitor centres. While it may have been a pain for us, it could have been a new experience for the local animals. Due to the temporary closure of US National Parks during the pandemic, Gaynor et al. carried out a ‘pseudonatural’ experiment, according to a 2025 research paper titled “The influence of human presence and footprint on animal space use in US national parks,” published in the Proceedings of the Royal Society B, to see how animals reacted to the separation between permanent infrastructure like roads, buildings, etc., and temporary human interaction. So, the question that arose was: do animals behave differently if there are no people around, but still on the pavement?

The study behind the question

As detailed in the same Proceedings of the Royal Society B paper, the team used GPS data of 229 individuals from 10 mammal species in 14 parks to see how animals used the area in 2019 (when parks were open) and 2020 (when parks were closed). The USGS publication record lists the same study. It found that, averaged across all parks and species, animals avoided the human footprint whether the park was open or closed. Not exactly a ‘wildlife takeover’, and this held even in remote parks. The exception was in more developed parks, where some animals that had avoided human areas in 2019 began selecting for them in 2020, but this was a localized shift among specific species, not an overall reversal from avoidance to preference.


Where it got interesting

In more developed parks, animals that avoided human areas in 2019 started to use these areas in 2020. Some continued to do this after the parks reopened. However, in most parks, animals continued to avoid human structures. According to the National Park Service’s summary of the research, behavioural changes appeared in some areas during the shutdown period, but it did not cause a complete change.

Whilst you may expect all animals to react the same, the study found that wolves and mountain goats always reacted negatively to human interaction. Mule deer and red foxes reacted positively. Elk and mountain lions had an exposure-mediated response; their reaction to human interaction depended on how much they had interacted with people. Black bears and moose had a stronger response to the closure. Researchers emphasise that different species, populations and individuals will have different behaviours.

A pause with a name

This isn’t the first time scientists have noticed the lockdowns could be a good opportunity for research. Rutz et al. in their 2020 paper titled “COVID-19 lockdown allows researchers to quantify the effects of human activity on wildlife,” published in the journal Nature Ecology & Evolution, noted that the drastic reduction in human movement during the pandemic could provide insight into how humans interact with wildlife.

They suggested referring to this period as the ‘anthropause’. This was a commentary paper rather than a results-based paper and was produced early on in the pandemic. They noted that anecdotal evidence suggested that some species were enjoying the calm, whilst others appeared to be under more pressure. This is exactly the type of data they were hoping for in 2025 with the national parks study.

The takeaway

The researchers don’t give a conclusion, and neither will we. They note that increased visitation to many protected areas has caused concern over how humans affect wildlife. Their results suggest that it depends on the area and species. It is still worth remembering, the next time you’re sitting in a queue of cars at a trailhead, that the parks are home to animals whose reactions to us vary enormously by species, by place, and even by individual.