Siemel's accomplishments in pursuing the large and often dangerous jaguar, the biggest cat in the Western Hemisphere and third-largest in the world, are deemed all the more impressive because on many of his hunts, he was reportedly armed only with a spear.

In the article "Interviewing the Tiger-Man", Siemel said, "… I learned the art from a poor native who had nothing but a home-made spear, where I had my high-powered rifle.

While I would not want to say that hunting big cats with a rifle cannot be plenty dangerous and exciting under all circumstances, particularly so in our Mato Grosso jungles, where vision is extremely limited, it seems to me that the bow complements the spear.

"[2] With his skill as a hunter, Siemel worked on ranches of the Pantanal hunting jaguars, or onças, hired by landowners to protect their livestock.

During this time, Siemel became an actor, appearing in the 1937 15-episode Frank Buck serial Jungle Menace as Tiger Van Dorn.

Siemel was interviewed by journalist Charles Collingwood for the Adventure series produced by the American Museum of Natural History, and broadcast on the CBS television network in 1953.

In 1963, the Sasha Siemel Museum and Store opened in Perkiomenville, Pennsylvania, in a century-old former story mill located on the Perkiomen Creek.

The museum housed Siemel's collection of hunting trophies, works of art, curios, minerals, shells, coins, weapons, Indian utensils, and many other items.

"Among the most interesting of the displays are Sasha Siemel's mementos of his many years of daring adventures and explorations as the only White man to hunt jaguars armed with a hand-made spear.

Charles Collingwood, narrator of the Adventure series, interviews Sasha Siemel, a professional hunter for 35 years who makes his living spear hunting jaguars for cattle ranchers in South America.

Siemel, who has lectured at the AMNH, shows films of various forms of wildlife around his home in Matto Grosso, Brazil, and also lets the viewers see his hunting activities: capturing a cub in the jungle and spearing a jaguar.