Angulate tortoises can be fairly easy keepers if they are provided with the appropriate diet and suitable environmental conditions. As with most tortoises, angulates thrive outdoors, at least in my warm and dry area. I have no experience in keeping them in a hot and humid climate like Florida or Hawaii. Basically, I care for my angulates pretty much the same way I do for my golden / Mesopotamian Greek tortoises.
In the wild, angulate tortoises' diet varies depending on the season and the region where they live. They eat grasses, herbs, annuals, and succulents. Sometimes they also consume snails, mushrooms, insects, and feces of other animals.
In captivity, a herbivorous diet is recommended. Angulate tortoises can be offered same foods as Greeks and star tortoises, but their diet should preferably be rich in succulents. Try to include plants from their native habitat as well.
Typical food items in captivity include opuntia cactus, various succulents (e.g. sedums, echeveria), garden weeds (e.g. dandelion, clover, plantain), grasses, leaves (e.g. hibiscus, mulberry), flowers (e.g. hibiscus, dandelion, petunia), some grocery store greens (e.g. endive, escarole, radicchio, winter dandelion), and possibly a little bit of squash occasionally (butternut, zucchini, pumpkin).
Note: All sedums, except Sedum acre, are generally considered safe for tortoises. Do not feed Sedum acre. It's believed to be toxic. Misty Corton in South Africa (scroll down to link) also lists Sedum morganianum and Sedum frutescens as unsuitable for angulate tortoises due to their high oxalate content.
As with other herbivorous tortoises, angulate tortoises' diet should be low in sugar. It may be wise to avoid feeding too much fruit, if any, because large amounts of fruit can promote flagellate (microscopic parasites) proliferation. Some keepers count squashes as vegetables and others as fruit.
If you live in a cold area, you may want to bring your angulate in for the cold months. When indoors, strong UV lights like the high output (HO) T-5 reptile UVB fluorescent linear (long) tubes from Arcadia or Zoo Med are ideal. Use separate basking bulbs with the T-5 tubes. See the lighting page.
Angulate tortoise keepers use various indoor substrates, including fir bark, plain soil, coco coir, soil/coco coir mix, coconut husk chips, sphagnum moss, or a mix of any of these. Add a bunch of real or artificial plants to create hiding places.
Clean drinking water should be available at all times. Baby angulate tortoises can be soaked (bathed to encourage drinking) daily and then less frequently as they grow.
Newly hatched angulate babies spend their first days or weeks in a warm incubator nursery on wet paper towels. I add edible plants for eating and hiding and maybe also a shallow bottle cap for water.
Later on, I move babies to a baby tub. These babies are golden Greeks, but I raise my angulates the same way. During the day, the basking bulb heats the wet sphagnum moss. A UV fluorescent tube is also turned on for part of the day. In the evening, I turn off the basking bulb. With open top tubs, I use no heat at night because the temperature in my tortoise room usually stays above 68-70 °F even in the winter.
You can also use a warm and humid vivarium (fully closed enclosure, closed chamber) to raise angulate babies. You can create a DIY vivarium from a taller plastic tub or glass tank with the lights attached inside and a solid lid placed on top. If you are working with plastic, be careful not to create a melting or fire hazard. With vivariums, you need to check the inside temperature and humidity frequently to keep them at an acceptable level.
My angulate babies love to hide and sleep in the warm, damp sphagnum moss. Every morning I dump warm water into the moss and stir it with my hands.
a.) Old recommendation
Captive angulate tortoises are said to be susceptible to respiratory infections, skin infections, and shell rot if they are kept in a too damp environment. Some keepers have experienced tragic consequences, illness and death, from raising angulates too wet and cold. Constant high humidity was believed to be their "worst enemy" in captivity and the traditional recommendation was to keep angulates "bone dry."
b.) Current thinking
However, if tortoises are kept too dry, they are prone to chronic dehydration which can lead to kidney problems and urinary stone formation. Both can be fatal. Baby tortoises can dehydrate especially quickly. Constant dry conditions are not recommended any more.
c.) Keep babies more humid
Jasser-Häger and Philippen recommend a higher humidity level for angulate tortoise hatchlings and youngsters (Testudo mag, 2003). If young ones are kept in too dry conditions, they can become "Toblerone tortoises." This description makes reference to pyramided tortoises with bumpy shell growth. Toblerone is a Swiss chocolate bar shaped like a row of pyramids.
I raise my angulate hatchlings in open top tubs in my warm tortoise room, but I have also used warm and humid incubators as baby nurseries. The smallest babies like to dig into the damp New Zealand sphagnum moss under their basking lights and sleep there. During the warm months, they often spend part of the day outside. I water the baby outdoor pens just like I water the adult pens.
Angulate tortoises thrive outdoors when the weather is suitable. In warm regions, they can possibly stay outdoors year round. In cold climate areas, they should be moved indoors during wet, chilly nights and freezes unless you provide them with a heated outdoor house. Some keepers even let them brumate (hibernate).
[Definition: Mammals hibernate and reptiles brumate. Brumation is a milder, less deep form of dormancy. In the wild, a brumating tortoise may temporarily wake up, move around, and even drink water on warmer days before returning to brumation.]
Adult angulate tortoises need large outdoor areas with well draining soil. Avoid substrates that retain too much water and stay soaking wet all the time. Plant food and shade plants in the enclosure and provide various hiding places.
Always keep bowls of fresh drinking water available. Replenish the water at least daily, or as needed, to keep it clean and cool. I see my angulates use their outdoor water bowls every so often, and when they drink, they drink a lot!
To combat excessive habitat dryness, you can water the enclosure in the morning and then let the substrate dry out during the day. This simulates native coastal conditions. Just check that not all of the substrate is constantly soaking wet. Provide some dryer areas as well for the tortoise to choose the conditions he needs.
As we get no summer rains, I water my outdoor pens as needed. On hot days I water more frequently depending on the temperature. During warmer weather, my angulates seek out the more moist areas under bushes.
Angulate tortoises, especially males, can be fairly active. In the wild, their activity temperature range has been observed to be 60-85 °F (15-29 °C).
Adult angulate tortoise drinking water. Tip: If you sink the water tray into the ground, it's easier for the tortoise to access it (not shown).
Angulate tortoise in her outdoor pen. Like all tortoises, she likes to hide in plants.
Unfortunately, info published on angulate / bowsprit tortoises (Chersina angulata) rarely covers captive care, but there are a few caresheets.
1.) The 2002 caresheet by Misty Corton in South Africa. Misty Corton's web page includes a long list of plants these tortoises eat in their native habitat. (Note: This site is now gone, but you can still read the page at the Internet Archive.)
2.) The June 2003 issue of the Testudo magazine by Die Schildkröten-Interessengemeinschaft Schweiz (SIGS in Switzerland) covers the angulate tortoise. The Testudo magazine is published in German, but you can copy the text from the pdf file and then translate it online. The paper is "Bemerkungen zur Zucht der Afrikanischen Schnabelbrustschildkröte" by Irmtraud Jasser-Häger and Hans-Dieter Philippen.
3.) Thomas Bauer from Germany describes his captive care and breeding of angulate tortoises in the 2006 book Turtles: Proceedings: International Turtle & Tortoise Symposium (Edition Chimaira).
4.) The October 2018 Reptiles Magazine has an article about angulates written by Chris Leone of Garden State Tortoise. (Note: I believe he has stopped keeping this species.)