Behaviour during oestrus: The tigress becomes restless. She gives vent to moaning calls and moves around spraying scent. She drinks water more frequently about 3-4 times a day.
When a tigress comes in contact with another male, she is cautious as the tiger is much larger. Normally a tiger will make a purring sound when the tigress moves closer indicating his interest in mating. They may take few hours to upto a day to develop mutual confidence. Once she develops confidence, then she will roll over her back in a playful manner. When they are in a playful mood, you can see their tails moving left to right with spring in their steps, rubbing of face and body etc.
Once mating starts, then it happens at frequent intervals with about 20 times a day. Studies with captive tigers have shown that frequency is more and can go upto 52 times.
The tigress moves closer to the male and rubs her face. Most of the times when the tigress comes closer, the tiger gets up and is ready. At times a gentle nudge also does the trick. The tigress lies on her belly and the tiger mounts her. The tigress moves her tail to one side. When the actual entry happens, the tiger grabs the tigress by the scruff of her neck. This period lasts for about 10-15 seconds. The end is signalled by a loud roar. The tigress turns her head and takes a swipe at the tiger with her forleg. The tiger instinctively takes evasive action. The tigress then rolls over her back to facilitate penetration of the semen.
At times when a transient male tiger passes through the area, and its dominance is not clearly established the female engages in false mating. During that time, she won't roll over her back.
The following image is when the acutal ejaculation happened and the female has already started its roar and is about to turn her head and take a swipe at the male. This mating sequence was timed at 47 seconds with the actual mounting lasting for 10 seconds.
Canon EOS 1D Mark II, Canon EF 28-135 f3.5-5.6 IS, ISO 100, f5.6, 1/80 sec, full frame.