What if humans never evolved?

If humans had never evolved, Earth would probably be much wilder and less altered by technology, but the exact result is impossible to know.

Most likely, there would be:

• No agriculture, cities, factories, roads, plastics, or large-scale deforestation
• No human-caused climate change, though natural climate change would still occur
• Less fragmented ecosystems, with many forests, wetlands, grasslands, and oceans under far less pressure
• No domesticated species as we know them, such as dogs, cattle, chickens, or modern crop plants
• Different outcomes for other hominins, if they survived at all

Some extinct animals might still be around today if humans had never existed, including species such as mammoths, giant ground sloths, glyptodons, cave bears, straight-tusked elephants, and wild horses. But that is not something we can know for sure, because many of those species were also affected by climate shifts and other natural pressures.

It is also possible that marine ecosystems would be very different, with larger whale populations and stronger predator populations such as sharks, because human fishing and hunting would never have occurred. But the exact balance of marine food webs would still depend on natural evolution and climate.

So the safest short answer is: Earth would likely be far less modified by biology and more governed by natural ecological processes, but we cannot reliably say which exact species or ecosystems would exist today.