Desert tortoises (Gopherus agassizii) are a long-lived reptile vulnerable to predation by many predators, including desert kit foxes (Vulpes macrotis arsipus) and coyotes (Canis latrans). From 2009 to 2014, we assessed canid food habits at a study site in the Mojave Desert in California, USA, by collecting and analyzing desert kit fox and coyote scats. These canids primarily consumed small mammals and invertebrates. Desert tortoise remains occurred at an overall low frequency (<3%), indicating the opportunistic use by these canids of desert tortoise as a prey or scavenged food item. When we analyzed the desert tortoise remains further, there was a significant difference between predator type and desert tortoise age class. Coyotes consumed more than twice as many adult than juvenile desert tortoises, while desert kit foxes only consumed juveniles. Desert kit foxes are a small canid, thus limited to smaller prey items (i.e., juvenile desert tortoises), while coyotes are larger and can optimize a wider size range.

沙漠龟（Gopherus agassizii）是一种长寿的爬行动物，易受许多掠食者捕食，包括沙漠工具狐狸（Vulpes macrotis arsipus）和土狼（Canis latrans）。从2009年到2014年，我们通过收集和分析沙漠工具箱狐狸和土狼的粪便，评估了美国加利福尼亚州莫哈维沙漠中一个研究地点的犬类饮食习惯。这些犬科动物主要食用小型哺乳动物和无脊椎动物。沙漠龟的遗骸总体出现频率较低（<3％），表明这些沙漠龟的机会性地将其用作猎物或被清除的食物。当我们进一步分析沙漠龟的残留时，捕食者类型和沙漠龟年龄类别之间存在显着差异。土狼消耗的成年动物是幼年沙漠龟的两倍多，而沙漠工具箱的狐狸只消耗幼年动物。沙漠工具箱的狐狸是一种小型犬科动物，因此仅限于较小的猎物（例如，少年沙漠龟），而土狼则较大，可以优化更宽的尺寸范围。