Reindeer herding is one of the few forms of nomadic or shifting agriculture practised outside the tropics.

Explanation:
Reindeer herding is a traditional livelihood and land use practice primarily found in the Arctic and sub-Arctic regions of the northern hemisphere, such as Scandinavia, Russia, Alaska, and Canada. It involves the domestication and management of reindeer for various purposes, including meat, milk, fur, and transportation.

Nomadic or Shifting Agriculture:
Nomadic or shifting agriculture is a type of subsistence farming where farmers move from one area to another in search of fertile land for cultivation. This form of agriculture is commonly practiced in tropical regions, where the soil is often poor in nutrients and needs time to regenerate.

Reindeer Herding Outside the Tropics:
Reindeer herding, on the other hand, is primarily practiced in Arctic and sub-Arctic regions, which are characterized by cold climates and tundra or taiga ecosystems. These regions have unique environmental conditions that make it suitable for reindeer herding. Here's why reindeer herding is considered one of the few forms of nomadic or shifting agriculture outside the tropics:

1. Adaptation to Cold Climate: Reindeer are well adapted to the harsh and cold environments of the Arctic and sub-Arctic regions. They have thick fur, a layer of insulating fat, and specialized hooves that allow them to navigate through snow and ice-covered landscapes.

2. Seasonal Migration: Reindeer herding involves seasonal migration, where herders move their herds between different grazing areas throughout the year. This movement is driven by the availability of food and the need to avoid overgrazing in a particular area.

3. Sustainable Land Use: Reindeer herding is a form of sustainable land use as it allows the tundra vegetation to recover during periods when the herds are not present in a specific area. This rotational grazing system helps maintain the ecological balance and prevents overexploitation of resources.

4. Cultural Significance: Reindeer herding has deep cultural significance for indigenous communities living in the Arctic and sub-Arctic regions. It is an integral part of their identity, traditions, and livelihoods, preserving their cultural heritage and knowledge of the land.

In conclusion, reindeer herding is indeed one of the few forms of nomadic or shifting agriculture practiced outside the tropics. Its unique adaptation to cold climates, seasonal migration patterns, sustainable land use practices, and cultural significance make it a distinct form of agriculture in the Arctic and sub-Arctic regions.