diff --git a/include/pet.hpp b/include/pet.hpp
new file mode 100644
index 0000000..a753f41
--- /dev/null
+++ b/include/pet.hpp
@@ -0,0 +1,21 @@
+#pragma once
+#include <Arduino.h>
+#define MAXIMUM_STAT 100
+
+class Pet {
+  public:
+    Pet();
+    bool isAlive;
+
+    void updateHunger(int8_t delta);
+    void updateJoy(int8_t delta);
+    void updateEnergy(int8_t delta);
+    void updateCleanliness(int8_t delta);
+    String getReasonForDeath() const;
+  private:
+    int8_t hunger;
+    int8_t joy;
+    int8_t energy;
+    int8_t cleanliness;
+    String reasonForDeath;
+};
diff --git a/src/pet.cpp b/src/pet.cpp
new file mode 100644
index 0000000..c370523
--- /dev/null
+++ b/src/pet.cpp
@@ -0,0 +1,68 @@
+#include "pet.hpp"
+
+Pet::Pet()
+    : isAlive(true), hunger(0), joy(100), energy(100), cleanliness(100), reasonForDeath("") {}
+
+void Pet::updateHunger(int8_t delta) {
+  hunger += delta;
+
+  if (hunger < 0) {
+    isAlive = false;
+    reasonForDeath = "starvation";
+    return;
+  }
+
+  if (hunger > MAXIMUM_STAT) {
+    isAlive = false;
+    reasonForDeath = "overfeeding";
+  }
+}
+
+void Pet::updateJoy(int8_t delta) {
+  joy += delta;
+
+  if (joy < 0) {
+    isAlive = false;
+    reasonForDeath = "depression";
+    return;
+  }
+
+  if (joy > MAXIMUM_STAT) {
+    isAlive = false;
+    reasonForDeath = "overstimulation";
+  }
+}
+
+void Pet::updateEnergy(int8_t delta) {
+  energy += delta;
+
+  if (energy < 0) {
+    isAlive = false;
+    reasonForDeath = "exhaustion";
+    return;
+  }
+
+  if (energy > MAXIMUM_STAT) {
+    isAlive = false;
+    reasonForDeath = "overresting";
+  }
+}
+
+void Pet::updateCleanliness(int8_t delta) {
+  cleanliness += delta;
+
+  if (cleanliness < 0) {
+    isAlive = false;
+    reasonForDeath = "disease";
+    return;
+  }
+
+  if (cleanliness > MAXIMUM_STAT) {
+    isAlive = false;
+    reasonForDeath = "overcleaning";
+  }
+}
+
+String Pet::getReasonForDeath() const {
+  return reasonForDeath;
+}