The process of estimating the number of tigers in a given area is called ‘Tiger census.’ 

• This exercise provides us with an estimate of tiger number, density and change in tiger indices – a measure of tiger occupancy in a given area. 
• It is conducted at regular intervals to know the current tiger populations and population trends. 
• Besides estimating the number of tigers, the method also helps to gather information on the density of the tiger populations and associated prey. 
• The most commonly used technique in the past was ‘Pugmark Census Technique’. 

• In this method the imprints of the pugmark of the tiger were recorded and used as a basis for identification of individuals.  
• Now it is largely used as one of the indices of tiger occurrence and relative abundance. 

Source: Shankar