Octopus vulgaris has an EQ of about 0.02. Sepia officinalis (the common cuttlefish) has an EQ of about 0.09.

By contrast, rabbits have an EQ of about 0.4. So octopuses are actually dumber than the dumbest mammals. They're also smarter than reptiles and probably about as smart as some birds.

Wikipedia:

Manta rays have the highest for a fish,[16] and either octopuses[9] or jumping spiders[17] have the highest for an invertebrate. Despite the jumping spider having a huge brain for its size, it is minuscule in absolute terms, and humans have a much higher EQ, despite having a lower raw brain-to-body weight ratio.[18][19][20] Mean EQ for reptiles are about one tenth of the EQ for mammals. EQ in birds (and estimated EQ in dinosaurs) generally also falls below that of mammals, possibly due to lower thermoregulation and/or motor control demands.[21] Estimation of brain size in the oldest known bird, Archaeopteryx, shows it had an EQ well above the reptilian range, and just below that of living birds.[22]

Cows and pigs don't have the equipment to use tools, manipulate the environment, or produce symbols we recognize. They're quadripedal and rely on all four legs for support. Are animals with hands automatically smarter than animals without them? Probably not. Sure, they don't have a large area of motor cortex devoted to doing things with their hands because they don't have any, but we haven't done enough studies on cows and pigs to say much about their minds.

A lot of the species we recognize as 'intelligent' are often predators, which I find interesting, but not surprising, as they have to be able to plan to catch their prey, whereas prey animals just have to not get caught.