Sulcata Nutrition: the 90% rule and Avoiding Shell Deformities

Susan’s Pro-Tip: "Tortoises can actually become 'addicted' to certain foods. Don't let them. Provide a wide range of suitable forage so they don't become picky eaters."
Susan Tellem, Founder
Susan Tellem
Founder, World Turtle Day® & American Tortoise Rescue®

African Spurred Tortoises (Sulcatas) are massive, voracious eaters—I often call them the “vacuums” of the sub-Sahara. In their native Sahel, food is scarce and very high in fiber. In captivity, however, we have a tendency to “kill them with kindness” by overfeeding the wrong things.

The Golden Rule: Fiber is King

Wild tortoise feces are well-compacted, firm, and almost entirely composed of varied grasses. To replicate this, a high fiber intake of grasses, hay, and weeds should form 90% of your tortoise’s diet. If you see loose or runny stools, it’s a sign your tortoise is missing that critical roughage.

What to Put on the Plate:

  • The 90% Base: Coarse mixed grasses (grass hay), sow thistle, clover, and dandelions. Dark leafy greens like Romaine (never Iceberg!), escarole, endive, chard, and turnip greens are excellent.
  • The Cactus Factor: Cactus paddles and prickly pears are absolute favorites and provide great hydration.
  • Mazuri Tortoise Food: I have never met a tortoise that didn’t love it. I buy 25lb bags and wet the pellets to soften them.

What to Absolutely Avoid:

  • Animal Protein: While they will eat it, it is toxic to them. It causes carapace deformity, kidney failure, and a tragically shortened life.
  • The “Rich” Veggie Trap: Avoid excessive beans, peas, or sprouts. These are too protein-rich and lead to “pyramiding” (bumpy shells).
  • Goitrogenic Hazards: Go easy on broccoli, kale, and cabbage; too much can lead to goiter and hypothyroidism 

🐢 A Quick Note from our team:

While many of the stories, photos, and life-saving care tips found in our Resource Hub were born during our 35 years at our Malibu, California sanctuary, please note that as of late 2025, American Tortoise Rescue no longer operates a physical sanctuary location.

Don’t worry—the mission hasn’t skipped a beat! Our beloved resident “shellebrities” are enjoying their golden years at Turtle and Tortoise Rescue of Arroyo Grande up the coast, and our work has shifted entirely to global advocacy, education, and shellebration. While we no longer take in new surrenders at a physical site, we are more dedicated than ever to helping you “shellebrate” and protect turtles in your own backyard!

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