Charles and Jon talk to mammalwatcher and environmental lawyer Brett Hartl from his home in Prescott, Arizona.

After beginning his working life as a ranger in Montana's Glacier National Park, Brett went to law school and now coordinates the Center for Biological Diversity's work on federal legislative issues that affect endangered species and other environmental concerns.

Brett explains how - and why - he made the transition from a field biologist to environmental lawyer.

He explains the process behind mounting a legal case, using Wolverine protection as an example. And he outlines the vital role mammalwatchers can play in helping environmental advocacy groups mount a legal case (see notes below).

And Brett talks about some of his favorite mammalwatching adventures including bumping into a Wolverine in Montana and swimming with Blue Whales in Sri Lanka.

At the start of the episode we get an update from Marc Bozon about progress to date on his 2026 Big Cat Year. You can read all about Marc's adventures, and his support for conservation, on his website including his encounter with the mythical Bornean Bay Cat.

Notes: Brett explained that if any mammalwatcher has seen, tried to see, or has plans to see, a specific species then you could be key to mounting a legal case to protect a that animal, particularly for one of the more obscure mammals where it can be hard to find someone who would personally be harmed by that species' extinction. We, however, can legitimately explain why our hopes and dreams are in tatters if that particular vole or shrew were to disappear.

So if you would like to help US environmental advocacy groups protect mammals, then consider becoming a member of one of the key groups fighting to protect US wildlife: the Center for Biological Diversity, Defenders of Wildlife, NRDC, and/or Wildearth Guardians. If you would like to be a standing declarant in particular, feel free to reach out to Brett at bhartl@biologicaldiversity.org and he will keep your contact information for future legal fights to better protect mammals under the law.

You can support mammalwatching and buy us a coffee here https://buymeacoffee.com/mammalwatching

Finally did you know you can sign up to receive a weekly mammalwatching newsletter here? https://www.mammalwatching.com/subscribe-to-updates/

Cover art: Brett Hartl in the Central African Republic.

Dr Charles Foley is a mammalwatcher and biologist who, together with his wife Lara, spent 30 years studying elephants in Tanzania. They now run the Tanzania Conservation Research Program at the Lincoln Park Zoo in Chicago.

Jon Hall set up mammalwatching.com in 2005. Genetically Welsh, spiritually Australian, currently in New York City. He has looked for mammals in almost 120 countries.

Charles and Jon compare notes from their recent trips to China, and talk the joys of travel there, especially the country's superb mammalwatching opportunities.

Charles and his family spent 10 days in China's Qinghai Province in May, while Jon was in China for a month from mid-April, including almost two weeks in Yunnan Province and a few days in Qinghai.

We discuss the Gouli Valley, and the extraordinary carnivore watching there, due in large part to a guide with superhuman vision. Charles has a close encounter with some Tibetan caterpillar connoisseurs and Jon discovers that seeing any species might be possible with the help of the right friends in China, especially when one is the 'mammal lord'.

Notes: Jon's 2026 reports from China - Yunnan, Qinghai, Tangjiahe, Guangxi and Zhejiang - are already available on mammalwatching's China page. If you are interested in details of the tour he will lead across Qinghai next year, including to the original Valley of the Cats, please email.

The study of Fishers predating Lynxes that Charles discussed at the start is here.

If you would like to submit you own notes from the field then please get in touch with Jon at info@mammalwatching.com

You can support mammalwatching and buy us a coffee here https://buymeacoffee.com/mammalwatching

Finally did you know you can sign up to receive a weekly mammalwatching newsletter here? https://www.mammalwatching.com/subscribe-to-updates/

Cover art: Pallas’s Cat in the Gouli Valley, February 2026. Photograph by Man Fu.

Dr Charles Foley is a mammalwatcher and biologist who, together with his wife Lara, spent 30 years studying elephants in Tanzania. They now run the Tanzania Conservation Research Program at the Lincoln Park Zoo in Chicago.

Jon Hall set up mammalwatching.com in 2005. Genetically Welsh, spiritually Australian, currently in New York City. He has looked for mammals in almost 120 countries.

Charles and Jon talk to conservationists and primatologists Tom Butynski and Yvonne de Jong from their base in Kenya.

Tom and Yvonne run the East African Primate Diversity and Conservation Program and research primates and other mammals in East Africa.

After explaining how their rural childhoods fostered a love for nature, Tom and Yvonne outline very varied career paths that took them around the world and eventually to Kenya - and each other - 25 years ago.

They talk about the importance of citizen science and describe some of the work they are undertaking on a range of species, including the critically endangered Southern Patas Monkey. And they outline the process they have followed to describe the several new primate species and subspecies they have described.

Charles is delighted to hear that if people looking for a new purpose in life then "dik-diks are the way to go", while Jon is shocked when Yvonne claims that she and Tom are not yet "as cool as the birders"!

The episode begins with Charles and Jon taking about their March 2026 weekend in Florida featuring a Florida Mouse and a very lengthy wrong turn!

Notes: Tom and Yvonne's Wild Solutions website is a goldmine of mammalwatching information, including some excellent free pocket guides to African primates, and a sound library of vocal profiles of many galago species (the calls of which are often indispensable to species identification).

Jon and Charles's weekend in Florida report is here.

If you would like to submit you own notes from the field then please get in touch with Jon at info@mammalwatching.com

You can support mammalwatching and buy us a coffee here https://buymeacoffee.com/mammalwatching

Finally did you know you can sign up to receive a weekly mammalwatching newsletter here? https://www.mammalwatching.com/subscribe-to-updates/

Cover art: Tom & Yvonne in the field by Rick Strooper.

Dr Charles Foley is a mammalwatcher and biologist who, together with his wife Lara, spent 30 years studying elephants in Tanzania. They now run the Tanzania Conservation Research Program at the Lincoln Park Zoo in Chicago.

Jon Hall set up mammalwatching.com in 2005. Genetically Welsh, spiritually Australian, currently in New York City. He has looked for mammals in almost 120 countries.