10 animals as columns and as rows in a table. In the fields if they can be kept together (yes=+ , no=-). Find many different animals that can be kept together.
| Giraffe | Lion | Elephant | Zebra | Tiger | Bear | Gorilla | Monkey | Hippopotamus | |
|---|---|---|---|---|---|---|---|---|---|
| Giraffe | + | - | - | + | - | - | - | - | - |
| Lion | - | + | - | - | + | - | - | - | - |
| Elephant | - | - | + | + | - | - | - | - | + |
| Zebra | + | - | + | + | - | - | - | - | - |
| Tiger | - | + | - | - | + | - | - | - | - |
| Bear | - | - | - | - | - | + | - | - | - |
| Gorilla | - | - | - | - | - | - | + | - | - |
| Monkey | - | - | - | - | - | - | - | + | - |
| Hippopotamus | - | - | + | - | - | - | - | - | + |