where can these creatures be widely found?
Fossils were found in parts of North America, South America and as far as north Alberta, Canada.
Smilodon
 North America 
when did the saber toothed cat become extinct It became extinct 10,000 years ago in the Quaternary extinction event. what is smilodon? is a genus of the extinct machairodont subfamily of the felids. how does it look like? It is well-developed forelimbs and exceptionally long upper canine teeth and its jaw has a bigger gape than that of modern cats. how did it get its name? Lund named it Smilodon populator which the Ancient Greek meaning of "Smilodon" as ("smilē"), "scalpel" or "two-edged knife", and "οδόντος" ("odontús"), "tooth". how friendly is their behavior with humans? UNANSWERABLE
wiki:5317069
Smilodon [SEP] Distribution and habitat
"Smilodon" lived during the Pleistocene epoch (2.5 mya–10,000 years ago), and was perhaps the most recent of the saber-toothed cats. It probably lived in closed habitat such as forest or bush. Fossils of the genus have been found throughout the Americas. The habitat of North America varied from subtropical forests and savannah in the south, to treeless mammoth steppes in the north. "S. fatalis" fossils have been found as far north as Alberta, Canada. The mosaic vegetation of woods, shrubs, and grasses in southwestern North America supported large herbivores such as horses, bison, antelope, deer, camels, mammoths, mastodons, and ground sloths.