Phidippus johnsoni, commonly known as the Red‑Backed Jumping Spider or Johnson Jumping Spider, is one of the most distinctive and frequently encountered jumping spiders across western North America. Adults reach around 1 cm in length, with both sexes displaying a vivid red abdomen; females typically show a central black stripe, while males are more uniformly red. Their chelicerae shine an iridescent teal, contrasting sharply with the otherwise black body. This species is also a noted mimic of velvet ants (Mutillidae), adopting similar red‑and‑black warning colours that help deter predators.
 
In the wild, P. johnsoni occupies an impressive range—from the Pacific coast to the Great Plains, and from northern Mexico up into southern Canada—thriving in habitats as varied as coastal dunes, oak woodlands, and dry shrublands. They occur from sea level all the way to the tree line, reflecting a high degree of environmental adaptability. They construct conspicuous tubular silk retreats under rocks, logs, and debris, using these shelters for resting, moulting, egg‑laying, and protection during bad weather.
 
Behaviourally, this species is an active, daylight hunter that relies on keen vision and powerful leaps rather than webs to capture prey. They feed on a wide range of insects and are also known to prey heavily on other spiders. Courtship, mating, and even some territorial interactions occur within or near their silk retreats. Although generally confident and bold, cannibalism can occur—typically females consuming males. Their agility and striking colours make them one of the most charismatic salticids in their range