Reindeer harvesting can be done in groups or alone, with lone hunting generally requiring extra safety precautions. While reindeer harvesting is usually a pleasant experience and the following problems may never be encountered, it can also be exhausting and does entail some degree of safety risk. Good hygiene and adequate hydration can protect against infections, diarrhea, and gastroenteritis. A small first aid kit should be carried when away from the campsite or boat, and preparations should be made for the various hazards of outdoor recreation. The terrain can be hilly, mountainous, uneven, and stony, with hidden crevices or holes. It may also be marshy, muddy, and wet. It may be necessary to cross streams and rivers, and slippery rocks present a hazard. If there is snow and ice, there can be cornices, crevasses, and avalanches, although snow can make it easier to spot and track reindeer.