The great biological value of the hills of Monferrato is not limited to vegetable components but it also extends to zoological ones whose survival is however compromised because of the widespread clearing by man, pollution and hunting activity.
Rambling along the woodland paths it isn't unusual to find hedgehogs (Erinaceus europeus), shrews (Sorex araneus), and squirrels (Sciurus vulgaris), while others, that hide from sight, like the fox (Vulpes vulpes), badger (Meles meles), and weasel (Mustela nivalis), to name just a few of the most common mammals present in the area.
An important index of ecological-environmental quality, a symptom of low anthropic impact, is given by the value of the avifauna. In fact there are species from the leafy woods present and nesting that have become rare or have disappeared from other areas of Monferrato.
Among those are the green Woodpecker (Picus viridis), minor red Woodpecker (Picoides minor), the Cuckoo (Cuculus canorus), jay (Garrulus glandarius), and titmouse (Parus ater).
The nesting of diurnal predatory birds like the Buzzard (Buteo buteo), and the Kestrel (Falco tinnunculus) and nocturnal predatory birds like the Owl (Asio otus), Barn Owl (Tyto alba), and Tawny owl (Strix aluco) is of great importance too.
The presence of the toad (Bufo viridis), dalmatina frogs belonging to the 'red frog' group, the Salamander (Salamandra salamandra), Chalcides chalcides, and the crested newt (Triturus carnifex), have also been noted.
Among the reptiles are Slow-worms (Anguis fragilis), Natrix, natrix, Elaphe longissima, the Coluber viridiflavus, and the rare Common viper (Vipera aspis).
Especially at an entomological level the zoological treasures must be searched for. The ecological indication which enriches and makes the Crea hill system peculiar is the same as that of the plant system: besides the distributed rarity of the species, there is the contemporary presence of elements typical of extreme environments like that of the north African coasts or the Boreal forests.
Research on the lepidoptera which are present on Crea Hill have been carried out by world-famous researchers. Some of the discoveries resulted in new species for Piedmont and Italian fauna. The most significant discoveries in the area under examination unique to Italian territory are: Coleophora sisteronica, C. striolatella, C. pulmonariella, Acrolepiopsis tauricella, all tiny lepidoptera. The presence of other very rare species of micro-lepidoptera in Italy like the Microshpecia tineiformis, Scythris punctivittella and deltophora stictella have been found nowhere else in Piedmont apart from the Crea hills, and the diurnal butterflies, Thymelicus action, Lysandra Amanda.
Other entomological studies conducted on the Crea hills have taken a census of 78 species of Coleoptera Ground beetles of relevant ecological interest. From among these relic populations species of different ecology, and rare species emerged like the Carabus rossii, Platysma anthracinum and Platysma macrum, Gynandromorphus etruscus, Acinopus picipes and other rare species localized in Piedmont.
Recently a small beetle belonging to the Weevil family and to the Acalles genus which is new to Italy, has been recorded, as well as and two species of order Hymenoptera new to science: Stictopisthus sacromontis (dedicated to the Holy Mountain of Crea) and Mesochorus scaramozzinoi.