Floris van Breugel / Desert agave (Agave deserti) has skewered a ball of spines shed by neighboring Cholla cactus (Cylindropuntia bigelovii) Anza-Borrego State Park, California, USA March

Shattil & Rozinski,Shattil & Rozinski / Black bear (Ursus americanus) cub climbing a fence, Minnesota, USA, May.

Jack Dykinga / Close up of Saguaro cactus (Carnegiea gigantea) and Teddybear cholla (Cylindropuntia bigelovii) in evening light, Tucson Mountain Park, Arizona, USA

Claudio Contreras / Sonoran Desert with Teddy-bear cholla (Cylindropuntia bigelovii), Saguaro (Carnegiea gigantea) and Brittlebush (Encelia farinosa). El Colorado volcano in background. El Pinacate Biosphere Reserve, nor...

Claudio Contreras / Sonoran Desert with Saguaro (Carnegiea gigantea) and Teddy-bear Cholla (Cylindropuntia bigelovii) cactic, alongside Ocotillo (Fouquieria splendens). El Pinacate Biosphere Reserve, Sonoran Desert, nort...

Claudio Contreras / Teddy-bear cholla (Cylindropuntia bigelovii) in El Elegante volcano crater. El Pinacate Biosphere Reserve, northwest Mexico.

Claudio Contreras / Sonoran Desert on volcanic soil with Teddy-bear cholla (Cylindropuntia bigelovii), Saguaro (Carnegiea gigantea) and ocotillo (Fouquieria splendens). El Tecolote volcano, El Pinacate Biosphere Reserve,...

Tim Fitzharris / Teddy Bear Cholla (Cylindropuntia bigelovii) cacti, Crater Range, Arizona

Jouan Rius / Superstition mountain and Teddy Bear cholla cactus (Opuntia bigelovii) at sunset, Lost Dutchman State Park, Arizona, USA, April.

Jouan Rius / Teddy Bear cholla cactus (Opuntia bigelovii) flowers, Lost Dutchman State Park, Arizona, USA. April.

Jouan Rius / Teddy Bear cholla cactus (Opuntia bigelovii) flowers, Lost Dutchman State Park, Arizona, USA, April 2014.

Tim Fitzharris / Desert Bluebell (Phacelia campanularia) flowers and Teddy Bear Cholla (Cylindropuntia bigelovii) cacti in spring, Anza-Borrego Desert State Park, California