Here's why:
* Fossil Record Limitations: The fossil record for tigers is not particularly complete, especially for subspecies like the Bengal tiger. This is because fossilization is a rare occurrence, and finding remains of a species like a tiger, which lives in a forested environment, is even rarer.
* Subspecies Evolution: Subspecies like the Bengal tiger evolve within the same species, and their differences are primarily due to adaptations to their specific environments. These adaptations are usually not drastic enough to leave unique fossil signatures.
* Recent Evolution: Bengal tigers are believed to have diverged from other tiger subspecies relatively recently. There hasn't been enough time for significant evolutionary changes to leave a clear fossil record.
What we can learn:
* Tiger Ancestry: Scientists can use fossils of ancient tiger species and other related cat species to trace the evolutionary history of tigers.
* Geographic Distribution: Fossil evidence can help understand the geographical distribution of tiger ancestors and their migration patterns over time.
While we don't have specific Bengal tiger fossils, understanding the broader fossil record of tigers and their relatives helps us understand the evolution of these majestic animals.